Winpdb - A Platform Independent Python Debugger The Spam Therapist
Standard captcha are either broken or are an accessibility nuisance or both. In its most noble form - reCaptcha - it is used brilliantly to digitize books and provide people over at India with a living:
http://recaptcha.net
http://blogs.zdnet.com/security/?p=1835
http://www.w3.org/TR/turingtest/
Smart engineers all over the world are busy trying to invent the most inaccessible new generation captcha possible, which typically involves analyzing or playing around with images.
However, it came to my mind recently that there might be another way, accessible and more faithful to the original Turing test (en.wikipedia.org/wiki/Turing_test). Can a computer administer an effective textual reverse Turing test to block registration spam? Can Eliza, the friendly nonsensical therapist, the famous first Turing test runner up, do that?
Imagine you try to register a new account at web20.com and suddenly Eliza pops up and asks you to elaborate on why you chose to submit the spammy looking email address john23kjdsf784@mail.ru
Seriously, spam filters such as Akismet (for blogs) or Gmail have become so efficient that they have practically eliminated comment and email spam. By requiring a registrant to submit enough textual information it may be possible to apply these filters to registration spam.
In addition, such a conversation, while being entertaining enough for the casual registrant, can be too time consuming for professional-human-captcha-solvers, relieving the potential problem of relay attacks.
Finally, if a new developer vs spammer war ensues around chat captcha we will soon see the first computer to pass the Turing test 
I think gmail and akismet work by spotting similarity between arriving spam posts directed at many different users and sites. It’s hard for a single site, given a single input from an apparent user, to tell whether the input is valid or spam. But when gmail or akismet sees similar messages being posts simultaneously to 1000’s of users or sites, it’s easier to tell what’s happening.
Glad to see this site is still up! I haven’t looked here in a while.
Sure,
The idea is to use similar techniques to those of Akismet and Google, including the use of consolidation of information from many sites.
In fact, it may be possible to use Akismet directly behind the scenes.
Yes, you can use akismet behind the scenes (we use it on our servers) but I think they are possessive about the incoming multi-source data streams that they see, so you couldn’t really implement a similar function that worked as well, without independently building up a user base of comparable size.
Anyway, the traditional Turing test is administered by a human. The interesting and novel thing about captchas is they can be administered by computers. Eliza doesn’t make any attempt to tell whether it is talking to a computer. Emacs used to have a “zippy” function which output random Zippy the Pinhead quotes from a list, and a “psychoanalyze-pinhead” function that made Zippy talk to Eliza. The results were amusing.
I suggested Eliza as a symbol.
I do not believe Eliza should be used as is, rather a custom chat machine specialized for this purpose.
Nevertheless, chatting with such a robot could be fun if it has a personality, such as Eliza’s, Marvin the paranoid android or HAL 9000.