Captchas and anti-spam Gems

#Total RankDaily RankNameSummary
1735892recaptchaHelpers for the reCAPTCHA API
22,5012,604voight_kampffVoight-Kampff detects bots, spiders, crawlers and replicants
32,9903,518rakismetRakismet is the easiest way to integrate Akismet or TypePad's AntiSpam into your Rails ...
44,5502,286invisible_captchaUnobtrusive, flexible and simple spam protection for Rails applications using honeypot ...