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What about http://www.jracademy.com/~jtucek/email/index.php? This is a javascript solution, but I've been using it for years and it works great!

I use the Email Protector javascript decryptor. It lets tou proide a mail-to link without showing the email in plain text.

I'm not a programmer, so I just took some code over at http://www.jracademy.com/~jtucek/email/index.php and used it. The link still appears as a mailto: link, but if you look at the page source there is nothing for a harvester to find.

What do you mean, evolution isn't hill climbing?

It's an AI technique for search. linky Basically, the technique is to always try to minimize the error in some function. My point is that evolution does not do this when it comes to energy efficiency.

If it isn't more efficient (at survival), it won't last.

Again, not necessarily. An inefficient process may be more adaptive than an efficient one. An inefficient process will probably have more overlapping, redundant steps than a more efficient one. That would make it more fault tolerant and more able to handle changing environmental conditions.

Let's take the story of two organisims, a squirrel and a grasshopper. Say they both depend on a single nutrient for survival. The squirrel takes eight steps to get it and use it, and the grasshopper takes four. Some of these steps are internal (metabolic) and others external (behavioral). The squirrel gathers two kinds of food to get the nutrient, the grasshopper one. You'd think that, in a closed system, the grasshopper would win, right? It can get and metabolise the nutrient faster and more efficiently, right?

Not necessarily. :) The grasshopper's one food could disappear, leaving it SOL. The squirrel may depend on the same food, but it has a backup.

The grasshopper could dominate in retrieving all foods containing the nutrient, but because of the squirrel's more complex (and thus more adaptive) digestive system, it could just eat grasshoppers. :)

See? There are many more possibilities. Extreme efficiency eliminates complexity (and thus possibilities), and can be maladptive because of that.

Your mailto link would also fail for anyone with JS turned off... including IE users. You can't blame firefox for that.

If you want to hide you emails, convert the letters to their numerical equivs manually...

But then I realized that this was overkill (and overkill that was making my web page hard to maintain). There's no arms race between spybot authors and web page designers. Spambots don't go around trying to figure out how people have obfuscated their mailto: links. There are too many ways it can be done, So spambots don't bother with any scanning beyond simple pattern matching.

My email address may look easy to find to you, but you're a carbon based unit. No spambot is going to go around reverse-engineering scripts on the off chance they generate mailto:s. And if they did, your hex codes would be just as vulerable as my simple strings.

Have a look here.

And yet obfuscation seems to work quite well, at least in my experience. How can this be?

I can think of two big reasons. The first is that deobfuscation is harder than it looks. It's not just a matter of applying the reveral -- you also need to recognize which reversal to supply (dubyaNOSPAMwhitehouseNONEgov, dubya at whitehouse dot gov, dubyaFSCKSPAM@whitehouse.gov....)

The second reason is the spam culture. The spam industry does not seem to attract a lot of creative, intelligent people. I suppose there must be people working on abvanced spambots, or who send out thousand of random emails with webbug links. But I never seem to encounter them. I suspect that most spambots are sent out by unscrupulous people who don't care about how many invalid addresses are on their lists. It doesn't matter when your customers naive schmucks who answered a "10 million email addresses for only $500!" ad. Which they probably got through spam!

Incidentally, you obfuscate your mailto: links without forcing people to deobfuscate by hand. Jim Tuckek has written a handy little Javascript generator that uses a simple encryption to store an address in a hard-to-access form, then translates it back to text as needed.

On December 14, 1900, Max Planck presented experimental results in front of the German Physical Society and announced that they could best be explained if energy exists in discrete packets, which he called "quanta." Today is the 100th birthday of Quantum Physics. But many people who consider themselves "scientifically minded" are still baffled by the question - What does it all mean, anyway?

In a nutshell, the theory of quantum physics, first devised by Max Planck (a German scientist) about 100 years ago, states that energy can be best understood as existing in discrete packets, which he called "quanta". This can be demonstrated with a simple photoelectric effect experiment - energy from electromagnetic waves does not gradually increase but is measured out in discrete photonic packets, or "quanta".

For more information on Max Planck, visit this biographical website.

For a more in-depth, but still accessible definition of quantum physics, see this webpage part of an online encyclopedia of science.

HTH.

On December 14, 1900, Max Planck presented experimental results in front of the German Physical Society and announced that they could best be explained if energy exists in discrete packets, which he called "quanta." Today is the 100th birthday of Quantum Physics. But many people who consider themselves "scientifically minded" are still baffled by the question - What does it all mean, anyway?

In a nutshell, the theory of quantum physics, first devised by Max Planck (a German scientist) about 100 years ago, states that energy can be best understood as existing in discrete packets, which he called "quanta". This can be demonstrated with a simple photoelectric effect experiment - energy from electromagnetic waves does not gradually increase but is measured out in discrete photonic packets, or "quanta".

For more information on Max Planck, visit this biographical website.

For a more in-depth, but still accessible definition of quantum physics, see this webpage part of an online encyclopedia of science.

HTH.

Some spambots will render that correctly. Less likely, though, is if they'll render an email that has had this done to it: it's encrypted through javascript.

It is a rather impressive piece of work. Uses honest-to-god RSA.

You could also encrypt all email addresses, and then in your spambot trap, put really really CPU intensive javascript. You'll win either way: either the spambot doesn't do javascript, and it won't get your addresses, or it does do javascript, and they've just spent an eternity wasting time. It would work the same way as a tarpit, but it wouldn't eat nearly so many resources on your end.

If you're really clever, you could have the javascript do useful work, and then have the results of that work encoded into links in the page. You could then retrieve the results when the spider follows the link.

There was an idea called hashcash floating arount a while back. The idea was that an SMPT server would refuse to deliver email if the sender didn't provide a hash collsion of so many bits to some given value. The sender has to expend way assymetrically more resources to generate the collision than it takes the reciever to check it. That way on can impose a cost on sending a lot of email. It's not so much to be a burden on ordinary users, but if you need to send thousands of emails, it will add up.

There are 5 kinds of causes of bridge failures:

• Bad specification
• Bad design
• Bad construction
• Bad maintenance
• Accident or sabotage

Software doesn't usually have the extreme costs of a crash. Some exceptions do exist, like airplane navigation and medical instruments (and cases of bad software there is a concern, too), but in general, the cost of a crash is low compared to the cost of design, which is often very high. That means that cost cutting measures tend to focus on the design because that's where the costs are high, even though it's only that way because the other costs are low. So pointy haired managers will do their thing and we get software that sucks to some degree.

If software did have the same cost ratios of a bridge, you can be sure the design quality would not be skimped on, and better software would result. In the sense of "if the economic model could be applied" the analogy fits. But of course reality is that the economic model is not the same at all. So I see where he is coming from with his analogy, and it makes sense, but we can't use it to solve the problem of why software sucks so much.