Mollom could probably be used to detect attempt to post spam content, and then auto-delete users.
CPU power needed to do that is significantly higher than one needed for OCR (you can OCR on mobile phone, and Google's cat recognition was using 64'000 of CPU as far as I remember), so until computers are much more faster, and CPU power cheaper, this is a pretty good way to provide robot detection. ReCAPTCHA - it was good not so long ago and it still stops significant part of bots that would solve regular CAPTCHAsĪre You A Human PlayThru - a bit more time consuming for users, at least if normal CAPTCHA was readable, but at the moment most solid way I know, as it can't be replaced by software very well.Ĭonfident CAPTCHA - bases on human ability to recognize and name things we see. This kind of captcha is easily recognised by OCR software within bots.