Captchas and anti-spam Gems

#Total RankDaily RankNameSummary
1740778recaptchaHelpers for the reCAPTCHA API
22,4792,188voight_kampffVoight-Kampff detects bots, spiders, crawlers and replicants
33,0554,112rakismetRakismet is the easiest way to integrate Akismet or TypePad's AntiSpam into your Rails ...
44,2932,839invisible_captchaUnobtrusive, flexible and simple spam protection for Rails applications using honeypot ...