Wow, you're right, but it's even further: 1949. I had no idea. Right reason, totally wrong date. When my instructor said "they used to teach spin recovery a few years ago" I figured he meant 5, not 50...
If you'd like to read a little more about literacy and reading comprehension skills in the US over the last 200 years, you should check out Neil Postman, particularly his books "Amusing Ourselves To Death" and "Building A Bridge To The 18th Century". To sum up some complex books in a quick soundbite... is exactly what his books are about. His claim is that the modern human brain, used to gathering information at high bandwidth from largely visual sources -- television, in other words -- does a very good job of processing information presented that way and a considerably worse job of processing information that's presented in writing, in long and complicated sentences. In contrast, people in the 18th and 19th century, who did all their communication via written material, had very different mental processing habits and could easily parse speeches that were written the way 19th century books were written. They could keep track of multiple nested clauses: deeper stack, essentially. They didn't need or want emphatic or emotive speech because it didn't convey information in a way they were prepared to accept.
They're good books. Even though they're 20 years old, they're still controversial, but I learned a lot from reading his work.
Now there's a depressing thought. And it brings up even more questions: if I got it from work and its apparent value is $3K, is that, then, part of my work benefits package? Is it in-lieu-of-wages? Urgh.
For the record I was replying to the statement 'pilot licenses are made out of plastic'. A: there's no such thing as a pilot license: it's a certificate. B: mine is not made of plastic. Apparently some are, but Fossett had his certificate for a very, very long time, and since mine's 10 years old and is paper, it is not unreasonable to assume that his, too, was paper.
I didn't look at the photographs. This is slashdot, after all.
I may be wrong about this, but it's been my experience, observationally, that brand loyalty in the automotive industry is stronger than in any other industry I've ever seen. Can you think of *any* other product where people stick big decals on their brand-new product advertising that it's better than others? ("Eatin' Fords, Poopin' Dodges" and piles of ripped-off-Calvin-peeing-on-chevy-bowtie bumperstickers.) My grandfather went his whole life buying Fords. My father went almost his whole life buying Chevrolets. I've spent the last 10 years owning Subarus and as a result now my brother, aunt, cousin, mother, sis-in-law, and girlfriend also all own Subarus, half of them being on their second one. Go anywhere in Florida and you'll see more Mustangs than the entire number of Mercedes and Audis combined. Likewise in western Washington State or Colorado more Subarus than all German cars combined, and those people just keep buying the same cars every year.
I love the jag plug-in, by the way. I can't wait for Subaru to come out with one...
They discontinued teaching spin recovery in primary training in about 1995 because NTSB research indicated more people were being killed in crashes resulting from spin recovery training, than being killed in spins. A gruesome but pragmatic decision.
You're free to go get training in spin recovery yourself, and most instructors recommend it. I believe that qualifies as aerobatic instruction and parachutes are required, but I'm not sure.
I work for a Fortune 500 company and their approach is pretty realistic: anything with persistent memory (hard drives or static ram) has to have the persistent memory removed, documented, and destroyed securely. Everything else goes to recycling (trash) but under the IT person's discretion, so we can take stuff if we want it.
Here's the problem, and I've never gotten a good answer: if I grab, say, a Sun blade server that still sells for $3K on ebay, that we're getting rid of because we're tired of dealing with Sun, it's "mine". But the company bought that 3 years ago and has depreciated it, and claimed that depreciation on their taxes, so the item is now worth "$0". Now they've given it to me, and I go put it on ebay and sell it for $3K. Is that legal? Can they give me something that has value after they've claimed it has zero value?
As I've said elsewhere in this thread, *my* pilot cert is a piece of paper, printed in a laser printer, in black and white, and I had to cut it out of the middle of a full-size sheet and get it laminated myself. I got my license in 1999 (dec 31, as it so happens) and I bet Steve Fossett had his well before that, so I'm betting his is paper, too, unless he went and got it laminated.
*MY* pilot certificate was printed on a laser printer, in black, in the middle of an 8 1/2" x 11" piece of paper. I had to cut it out with scissors and get it laminated. If Fossett didn't bother with the lamination step, it would be pretty easy to DIY.
(I was somewhat annoyed, given that I'd spent $5000 for that bit of paper, that it wasn't just a little fancier.)
Not to be snide, but: >How could a disease with such a long incubation period not be recognized for over a century?
I think you've answered your own question.
All you need is for the disease symptoms to take longer to show up than the average lifespan of the victims and you have a basically invisible disease. Add doctors' general unwillingness to put 'cause of death: unknown' on death certificates, and put your disease in a place where young death from other diseases -- particularly cholera, yellow fever, and smallpox -- was completely rampant, and you have everything you need to make a disease run for fifty years invisibly. In 1910, there were still widely-respected doctors arguing that bad air was responsible for malaria and yellow fever. The idea that a viral infection could stay latent for 15 years after contraction was completely out of their experience.
Actually, a Cobalt Qube with no fan because it runs cool enough to not need it. It does a fine job of powering IPCop on its old 250mhz MIPS processor, providing a firewall, SQUID, and NAT for the house, and only using a handful of watts while doing it.
I use 70/30 and 60/40 both at home and at work. I have some 70/30 circuits I soldered up in 1974 that are still working. High-tin solders are harder to work with: it doesn't flow as easily and doesn't seem to be willing to bead up on a pad, so if you try and self-locate a small package -- a BGA or LLP -- using solder, it won't: it'll just bridge all over the place. Thankfully, at work we provide engineering samples, not commercial stuff, so we don't have to worry about RoHS and can keep using leaded solder.
Tin whiskers are a worry: there are documented cases of them destroying valuable equipment. But it's the future of electronics, so we better get busy figuring out if tin/copper or tin/silver or others can reduce the tendency of tin to whisker in the first place.
For the same reason that a large majority of drivers think they have above-average driving skills: you always think you're better at what you do than most other people who are doing the same thing. It's worse in jobs that attract strongly motivated people, like engineering and IT, because they're *really* convinced that they're all better than all their coworkers are. Every time their company screws them over with layoffs or unpaid overtime, they go find exactly the same job somewhere else and convince themselves that *this* time it will be different because they'll try harder and *this* time they'll be rewarded for their efforts.
Meanwhile, the companies are thrilled to have people leave every time they push them around because someone new will get paid a lot less, even though they're much less productive while they're being trained. But, hey, that's not the company's fault, and it managed to cut costs.
Unionized companies are for people who invest in treasury bonds: in for long-term, gradual improvement. Non-unionized companies are for people who play blackjack at casinos: massive gains anticipated by a player who doesn't realize the game is rigged.
There were rumors of a number of failed Russian space launches that left cosmonauts stuck in orbit during the '70's -- like there were actually people on Kosmos-434, for instance, and the lunar race was much closer than generally thought. I'm sure it's a load of hooey but I knew people who were very intense about it, spent nights listening for transmissions on their high-powered ham setups.
The designs I've looked at indicate that one possible plan is to lift a station into orbit, then drop the tether to earth to a large ship somewhere in the Pacific, so the bottom side can actually be moved around to avoid LEO satellites and such. (That kind of addresses 1 and 3.) One proposal is that you get a small cable dropped down, and start sending up small climbers on a one-way trip: they just provide mass for the outer extension of the cable, upwards from the space station. The nice thing about this system is that it would only lift the weight of the payload + climber (no fuel, which constitutes more than 90% of current rocket payloads.) So whatever payload it carries, if you need more you just send up another climber. It's slow -- a week to get up to the station -- but you just keep shipping stuff, and eventually you build yourself a second station, then a third... Which means, the first country to get one working has an *incredible* advantage, because they can build new ones at very low cost compared to competitors. Whoever gets the first one up will have a near-stranglehold on the space market thereafter.
I voted in the county where I was registered, a largely agricultural county. Not wealthy by any means. They had dozens of machines *and* paper ballots; the wait was maybe ten seconds for all the people wearing cowboy hats and driving pickup trucks.
My girlfriend voted in Denver county, in a precinct near the lowest-income area of Denver. Well, I should say she *tried* to vote there because they did *not* have any paper ballots, and they had about the same number of electronic voting machines as the place where I'd voted (20-ish) for a precinct with 20x as many people as mine. And the machines crashed, and kept crashing.
This pattern seems to have been repeated all across the Colorado Front Range, where 80% of the population lives: the rural low-income areas and the high-income areas had plenty of voting machines, the urban low-income areas had a small fraction as many, and those kept crashing repeatedly throughout the day.
It's hard to avoid noticing that the distribution of machines had very low correlation with population or income, but quite high correlation with the political tendencies of the precincts.
>So unless their goal was to have an entire country go WTF???
I realized something interesting a little while ago, about the supermodel/fashion industry: models who are exotic-looking are more attractive for advertising than ones who are conventionally beautiful. Compare Devon Aoki (the silent sword-swinger in the movie "Sin City" and a top model) to any winner of Miss America in the last 10 years. Devon isn't what you'd call pretty. People stare at her, they think "she's hot... I guess? yeah, yeah, she's definitely hot!" whereas Crystle Stewart is, as they say, just another pretty face. Point being: if you had an ad featuring Crystle, people would breeze right by it, whereas if you have a picture of Devon, people stare at it for a while, because it doesn't fit well into their pre-determined pattern of what's attractive and what isn't.
If you're paying good money to try and catch people's attention, guess which one you prefer? hence my assumption that precisely what we are doing right now, is precisely the result that the ad agency who designed those ads was intending. We, and millions of other people, are standing around talking about a Microsoft advertisement, when we could be spending our time talking about... well, *anything* else, that wouldn't have the word 'Microsoft' or 'Windows' repeatedly showing up. The question is whether Microsoft understands that, and whether cancellation is part of the plan or Microsoft's marketing people decided that it wasn't likely to get the ROI they expected.
You could find out! Well, maybe not 80, but Atomic Zombie has lots of plans for how to build your own recumbent bikes using cut-up old bikes and a MIG welder, and some of his are very, very fast. My recumbent does in the 30's on flat ground without even pushing very hard and on downhills it's just terrifying. Building your own bikes is a great DIY hardware project, and it's an area of active innovation: not all the problems have been solved and there is still room for people throwing stuff together in their garages to come up with some great ideas. Plus recumbents are really comfy. I prefer my upright bike, still, for some circumstances, but the 'bent is really cool.
Since power required to overcome air resistance rises as the cube of the speed (force rises as the square, as a function of the cross-sectional area) there's a big advantage to high elevation. Since power produced drops off roughly linearly(*) with elevation because of reduced oxygen for the rider, you gain more by going to higher elevations than you lose. Many long-standing Olympic cycling (and other speed-related sports) records were set at the 1968 Olympics in Mexico City, at 3200 meters elevation.
* as I recall, pressure drops off as an exponential function, roughly pressure = sealevel pressure * e ^ (temp / (acceleration of gravity * height in meters)) but don't quote me on that.
For extra credit, many solid-state sensors with optics systems are actually physically damaged by medium-power laser diodes -- stuff in the 20-200mW range (as found in DVD burners.) It'd take quite a bit of work to make a setup that could track the flash of a camera and shoot back a laser beam from a moving vehicle, but it'd fix the problem. Or civic-minded individuals could just go out on foot and do it by hand.
>must be made holistically, and not based on a single narrow "save the fill-in-the-blank" criterion.
I agree. So I'm asking, out of curiosity: how does a society which has basically decided that it doesn't consider any level of risk acceptable, continue? Any advance that has the potential of hurting people gets attacked and legislated or lawyerized out of existence. People in regulatory or law-making roles actively participate in this because they stand to lose their jobs and careers if they've been shown to support something that has a risk of injuring people -- even if it will, overall, save or enhance the lives of many more people.
How do we as a society make progress if nobody is allowed to be at risk? I argue: we won't progress. So how do we, as informed individuals, get society to accept that progress without risk is very unlikely?
They're not trying to improve customer satisfaction by getting you to buy Vista. They're trying to convince you that it was a good purchase. There's an *enormous* difference between those, summed up in the phrase "buyer's remorse". If you'd like to read some interesting stuff about the psychology of purchasing decisions, read "The Paradox Of Choice" by Barry Schwartz. A company can do more for itself long-term through making people glad they chose something, than it can by just selling more stuff, because those people will A: buy again, and B: be more willing to convince other people to do the same thing they did, in part to defend to themselves their purchase decisions. People who are not convinced that they chose well will let other people know that; people who think they DID purchase wisely, especially if they were questioning the choice but were convinced by someone else, are nigh-evangelical in their willingness to let other people know why their purchase was a SUPER GOOD IDEA. People *hate* self-doubt and will do weird things to convince themselves that their choices were good.
Slashdot Mirror
Wow, you're right, but it's even further: 1949. I had no idea. Right reason, totally wrong date.
When my instructor said "they used to teach spin recovery a few years ago" I figured he meant 5, not 50...
If you'd like to read a little more about literacy and reading comprehension skills in the US over the last 200 years, you should check out Neil Postman, particularly his books "Amusing Ourselves To Death" and "Building A Bridge To The 18th Century". To sum up some complex books in a quick soundbite... is exactly what his books are about.
His claim is that the modern human brain, used to gathering information at high bandwidth from largely visual sources -- television, in other words -- does a very good job of processing information presented that way and a considerably worse job of processing information that's presented in writing, in long and complicated sentences. In contrast, people in the 18th and 19th century, who did all their communication via written material, had very different mental processing habits and could easily parse speeches that were written the way 19th century books were written. They could keep track of multiple nested clauses: deeper stack, essentially. They didn't need or want emphatic or emotive speech because it didn't convey information in a way they were prepared to accept.
They're good books. Even though they're 20 years old, they're still controversial, but I learned a lot from reading his work.
Now there's a depressing thought.
And it brings up even more questions: if I got it from work and its apparent value is $3K, is that, then, part of my work benefits package? Is it in-lieu-of-wages? Urgh.
For the record I was replying to the statement 'pilot licenses are made out of plastic'.
A: there's no such thing as a pilot license: it's a certificate.
B: mine is not made of plastic. Apparently some are, but Fossett had his certificate for a very, very long time, and since mine's 10 years old and is paper, it is not unreasonable to assume that his, too, was paper.
I didn't look at the photographs. This is slashdot, after all.
I may be wrong about this, but it's been my experience, observationally, that brand loyalty in the automotive industry is stronger than in any other industry I've ever seen.
Can you think of *any* other product where people stick big decals on their brand-new product advertising that it's better than others? ("Eatin' Fords, Poopin' Dodges" and piles of ripped-off-Calvin-peeing-on-chevy-bowtie bumperstickers.)
My grandfather went his whole life buying Fords. My father went almost his whole life buying Chevrolets. I've spent the last 10 years owning Subarus and as a result now my brother, aunt, cousin, mother, sis-in-law, and girlfriend also all own Subarus, half of them being on their second one.
Go anywhere in Florida and you'll see more Mustangs than the entire number of Mercedes and Audis combined. Likewise in western Washington State or Colorado more Subarus than all German cars combined, and those people just keep buying the same cars every year.
I love the jag plug-in, by the way. I can't wait for Subaru to come out with one...
They discontinued teaching spin recovery in primary training in about 1995 because NTSB research indicated more people were being killed in crashes resulting from spin recovery training, than being killed in spins. A gruesome but pragmatic decision.
You're free to go get training in spin recovery yourself, and most instructors recommend it. I believe that qualifies as aerobatic instruction and parachutes are required, but I'm not sure.
I work for a Fortune 500 company and their approach is pretty realistic: anything with persistent memory (hard drives or static ram) has to have the persistent memory removed, documented, and destroyed securely.
Everything else goes to recycling (trash) but under the IT person's discretion, so we can take stuff if we want it.
Here's the problem, and I've never gotten a good answer: if I grab, say, a Sun blade server that still sells for $3K on ebay, that we're getting rid of because we're tired of dealing with Sun, it's "mine". But the company bought that 3 years ago and has depreciated it, and claimed that depreciation on their taxes, so the item is now worth "$0". Now they've given it to me, and I go put it on ebay and sell it for $3K.
Is that legal? Can they give me something that has value after they've claimed it has zero value?
As I've said elsewhere in this thread, *my* pilot cert is a piece of paper, printed in a laser printer, in black and white, and I had to cut it out of the middle of a full-size sheet and get it laminated myself. I got my license in 1999 (dec 31, as it so happens) and I bet Steve Fossett had his well before that, so I'm betting his is paper, too, unless he went and got it laminated.
*MY* pilot certificate was printed on a laser printer, in black, in the middle of an 8 1/2" x 11" piece of paper. I had to cut it out with scissors and get it laminated. If Fossett didn't bother with the lamination step, it would be pretty easy to DIY.
(I was somewhat annoyed, given that I'd spent $5000 for that bit of paper, that it wasn't just a little fancier.)
Not to be snide, but:
>How could a disease with such a long incubation period not be recognized for over a century?
I think you've answered your own question.
All you need is for the disease symptoms to take longer to show up than the average lifespan of the victims and you have a basically invisible disease.
Add doctors' general unwillingness to put 'cause of death: unknown' on death certificates, and put your disease in a place where young death from other diseases -- particularly cholera, yellow fever, and smallpox -- was completely rampant, and you have everything you need to make a disease run for fifty years invisibly.
In 1910, there were still widely-respected doctors arguing that bad air was responsible for malaria and yellow fever. The idea that a viral infection could stay latent for 15 years after contraction was completely out of their experience.
Actually, a Cobalt Qube with no fan because it runs cool enough to not need it. It does a fine job of powering IPCop on its old 250mhz MIPS processor, providing a firewall, SQUID, and NAT for the house, and only using a handful of watts while doing it.
I have fanless computers, you insensitive clod!
I use 70/30 and 60/40 both at home and at work. I have some 70/30 circuits I soldered up in 1974 that are still working.
High-tin solders are harder to work with: it doesn't flow as easily and doesn't seem to be willing to bead up on a pad, so if you try and self-locate a small package -- a BGA or LLP -- using solder, it won't: it'll just bridge all over the place. Thankfully, at work we provide engineering samples, not commercial stuff, so we don't have to worry about RoHS and can keep using leaded solder.
Tin whiskers are a worry: there are documented cases of them destroying valuable equipment. But it's the future of electronics, so we better get busy figuring out if tin/copper or tin/silver or others can reduce the tendency of tin to whisker in the first place.
For the same reason that a large majority of drivers think they have above-average driving skills: you always think you're better at what you do than most other people who are doing the same thing.
It's worse in jobs that attract strongly motivated people, like engineering and IT, because they're *really* convinced that they're all better than all their coworkers are.
Every time their company screws them over with layoffs or unpaid overtime, they go find exactly the same job somewhere else and convince themselves that *this* time it will be different because they'll try harder and *this* time they'll be rewarded for their efforts.
Meanwhile, the companies are thrilled to have people leave every time they push them around because someone new will get paid a lot less, even though they're much less productive while they're being trained. But, hey, that's not the company's fault, and it managed to cut costs.
Unionized companies are for people who invest in treasury bonds: in for long-term, gradual improvement. Non-unionized companies are for people who play blackjack at casinos: massive gains anticipated by a player who doesn't realize the game is rigged.
There were rumors of a number of failed Russian space launches that left cosmonauts stuck in orbit during the '70's -- like there were actually people on Kosmos-434, for instance, and the lunar race was much closer than generally thought. I'm sure it's a load of hooey but I knew people who were very intense about it, spent nights listening for transmissions on their high-powered ham setups.
For the same reason mechanics drive cars they can repair -- even if those cars break down more often than the ones with the hoods welded shut.
There, a car analogy.
The designs I've looked at indicate that one possible plan is to lift a station into orbit, then drop the tether to earth to a large ship somewhere in the Pacific, so the bottom side can actually be moved around to avoid LEO satellites and such. (That kind of addresses 1 and 3.) One proposal is that you get a small cable dropped down, and start sending up small climbers on a one-way trip: they just provide mass for the outer extension of the cable, upwards from the space station.
The nice thing about this system is that it would only lift the weight of the payload + climber (no fuel, which constitutes more than 90% of current rocket payloads.) So whatever payload it carries, if you need more you just send up another climber. It's slow -- a week to get up to the station -- but you just keep shipping stuff, and eventually you build yourself a second station, then a third...
Which means, the first country to get one working has an *incredible* advantage, because they can build new ones at very low cost compared to competitors. Whoever gets the first one up will have a near-stranglehold on the space market thereafter.
If Eva Longoria runs Windows rather than another OS, that means some geek has a much better chance of rooting her box!
Yes, I am ashamed of myself for typing that, in case you were wondering.
I voted in the county where I was registered, a largely agricultural county. Not wealthy by any means.
They had dozens of machines *and* paper ballots; the wait was maybe ten seconds for all the people wearing cowboy hats and driving pickup trucks.
My girlfriend voted in Denver county, in a precinct near the lowest-income area of Denver. Well, I should say she *tried* to vote there because they did *not* have any paper ballots, and they had about the same number of electronic voting machines as the place where I'd voted (20-ish) for a precinct with 20x as many people as mine. And the machines crashed, and kept crashing.
This pattern seems to have been repeated all across the Colorado Front Range, where 80% of the population lives: the rural low-income areas and the high-income areas had plenty of voting machines, the urban low-income areas had a small fraction as many, and those kept crashing repeatedly throughout the day.
It's hard to avoid noticing that the distribution of machines had very low correlation with population or income, but quite high correlation with the political tendencies of the precincts.
>So unless their goal was to have an entire country go WTF???
I realized something interesting a little while ago, about the supermodel/fashion industry: models who are exotic-looking are more attractive for advertising than ones who are conventionally beautiful. Compare Devon Aoki (the silent sword-swinger in the movie "Sin City" and a top model) to any winner of Miss America in the last 10 years. Devon isn't what you'd call pretty. People stare at her, they think "she's hot... I guess? yeah, yeah, she's definitely hot!" whereas Crystle Stewart is, as they say, just another pretty face. Point being: if you had an ad featuring Crystle, people would breeze right by it, whereas if you have a picture of Devon, people stare at it for a while, because it doesn't fit well into their pre-determined pattern of what's attractive and what isn't.
If you're paying good money to try and catch people's attention, guess which one you prefer? hence my assumption that precisely what we are doing right now, is precisely the result that the ad agency who designed those ads was intending. We, and millions of other people, are standing around talking about a Microsoft advertisement, when we could be spending our time talking about ... well, *anything* else, that wouldn't have the word 'Microsoft' or 'Windows' repeatedly showing up. The question is whether Microsoft understands that, and whether cancellation is part of the plan or Microsoft's marketing people decided that it wasn't likely to get the ROI they expected.
You could find out!
Well, maybe not 80, but Atomic Zombie has lots of plans for how to build your own recumbent bikes using cut-up old bikes and a MIG welder, and some of his are very, very fast. My recumbent does in the 30's on flat ground without even pushing very hard and on downhills it's just terrifying.
Building your own bikes is a great DIY hardware project, and it's an area of active innovation: not all the problems have been solved and there is still room for people throwing stuff together in their garages to come up with some great ideas. Plus recumbents are really comfy. I prefer my upright bike, still, for some circumstances, but the 'bent is really cool.
Since power required to overcome air resistance rises as the cube of the speed (force rises as the square, as a function of the cross-sectional area) there's a big advantage to high elevation. Since power produced drops off roughly linearly(*) with elevation because of reduced oxygen for the rider, you gain more by going to higher elevations than you lose. Many long-standing Olympic cycling (and other speed-related sports) records were set at the 1968 Olympics in Mexico City, at 3200 meters elevation.
* as I recall, pressure drops off as an exponential function, roughly pressure = sealevel pressure * e ^ (temp / (acceleration of gravity * height in meters)) but don't quote me on that.
For extra credit, many solid-state sensors with optics systems are actually physically damaged by medium-power laser diodes -- stuff in the 20-200mW range (as found in DVD burners.) It'd take quite a bit of work to make a setup that could track the flash of a camera and shoot back a laser beam from a moving vehicle, but it'd fix the problem. Or civic-minded individuals could just go out on foot and do it by hand.
>must be made holistically, and not based on a single narrow "save the fill-in-the-blank" criterion.
I agree.
So I'm asking, out of curiosity: how does a society which has basically decided that it doesn't consider any level of risk acceptable, continue? Any advance that has the potential of hurting people gets attacked and legislated or lawyerized out of existence. People in regulatory or law-making roles actively participate in this because they stand to lose their jobs and careers if they've been shown to support something that has a risk of injuring people -- even if it will, overall, save or enhance the lives of many more people.
How do we as a society make progress if nobody is allowed to be at risk? I argue: we won't progress. So how do we, as informed individuals, get society to accept that progress without risk is very unlikely?
They're not trying to improve customer satisfaction by getting you to buy Vista. They're trying to convince you that it was a good purchase. There's an *enormous* difference between those, summed up in the phrase "buyer's remorse". If you'd like to read some interesting stuff about the psychology of purchasing decisions, read "The Paradox Of Choice" by Barry Schwartz. A company can do more for itself long-term through making people glad they chose something, than it can by just selling more stuff, because those people will A: buy again, and B: be more willing to convince other people to do the same thing they did, in part to defend to themselves their purchase decisions. People who are not convinced that they chose well will let other people know that; people who think they DID purchase wisely, especially if they were questioning the choice but were convinced by someone else, are nigh-evangelical in their willingness to let other people know why their purchase was a SUPER GOOD IDEA. People *hate* self-doubt and will do weird things to convince themselves that their choices were good.