In what I can only describe as a brilliant move, spammers have developed a way to slip around captcha tests. The tactic involves infecting your PC with a bit of malware (a common starting point for these things). The next time you open Internet Explorer, what seems like a casual game appears, consisting of a virtual stripper and a captcha image. Entering the matching text causes the pixel-stripper to do what they usually do. Each image nets an article of clothing. Simple and effective.
Spammers take this ‘decoded’ text, feed it into the appropriate system (this process is automated, of course) and proceed to get whatever they were looking for behind the captcha.
Original source: BBC News
Where I heard it: Marketing Pilgrim