Cory Doctorow describes how some creative hackers are using people as bots to workaround 'captchas', images of distorted text, which is used to protect against bots by websites such as Hotmail and Register.com.
The ingenious crack is to offer a free porn site which requires that you key in the solution to a captcha — which has been inlined from Yahoo or Hotmail — before you can gain access. Free porn sites attract lots of users around the clock, and the spammers were able to generate captcha solutions fast enough to create as many throw-away email accounts as they wanted.
The darkside aside, I am impressed by their ingenuity. But then I guess it is easy to think outside the box if you were never inside the box to begin with.