Cloaking Detection?

drcrja asks: "I am conducting some academic research on the use of cloaking and how it affects search engine rankings (cloaking is the practice of delivering a specially optimized page to search engine spiders while delivering a completely different page to the user). I am currently using Alta Vista's Babel Fish to retrieve pages and compare those pages to the pages on the actual web sites but I am trying to find other methods of detecting cloaking. I am wondering if any members of the /. community have any experience with this?"

Comments

Re:Just follow the ion emissions

[irony nazi]

Well, that is the way to detect Vulcan cloaking, but in order to detect website cloaking, try some variation of the following:

Ingredients:
Computer
Perl
Internet Connection
LibWWW, UserAgent, and all the dependencies, I forgot which
Optional: Perl Cookbook, by Christianson and Torkingham.

Directions:
Start with the Perl Cookbook to give you a quick background of how to design an autonomous www agent that will crawl around gathering webpages. You can have them visit links or read from a list of links or whatever you want.

Read the documentation from the Perl UserAgent libs and figure out how to change the http headers to spoof various browsers. I've done this before. I think that I ended up going into the UserAgent code and doing this manually. I don't remember exactly how I accomplished this, I just remember that it was easy.

Now have to agents to crawl websites and compare output from one website using the "Spider" http headers with the output from spoofing the "IE" http headers. Websites would sometimes still think the IE headers were a robot. The key is to pause the request so that it is as though a human is reading the page/clicking the links/etc.

Keep track of the sites that are different or keep track of whatever stats that you need.

Mix, Stir, Burn, Enjoy.

I've actually done this type of thing before in order to test various IE only websites on non-IE browsers (non-MS computers). My results were that all of the pages the *require* IE render perfectly in Mozilla and most render fine in Opera. I still don't understand why businesses would *turn-away* potential customers only for having different http headers!

I'd make or modify an existing program to do this

[stienman]

I imagine wget or another HTTP client can be coaxed to spit out the spider and browser type strings associated with search engine spiders. It would be a simple, straightforward hack to make a script that would request a page twice, once reporting itself as a search engine (and requesting the robots.txt file for good measure) and secondly as a regular browser. Then do a simple compare.

You could give it a list of sites and it could go through dozens or hundreds of sites a minute, rather than you doing it by hand. You could have it save pages that show differences, or at least give you the URLs so you could load them later and study the differences (if that is a goal).

You could use PHP, perl, java, etc to do this very simply as well. I imagine a simple PHP script could well be less than 50 lines, and could even call your browser and load the two pages side by side each time it found a difference.

-Adam