There used to be hoardes of sites offering free downloads, quizzes, porn etc etc. You would have to solve a captcha to get through, but they were ‘stuck’ in an infinite loop. I always believed it was being used by spammers/hackers to bypass actual captcha elsewhere on the web. Its kinda genius, offloading the work to randoms looking for free stuff…
Oh, great, a new potential apocalypse trigger. Woop