Sblam!
Open-source implementation of server-side spam filtering of blog comments and forum posts. It's available as a free web service. It's open source, so you can set up your own server if you prefer. It's...
View ArticleAkismet
A spam filtering program that is free for personal use and you have to pay for corporate usage.
View ArticlereCAPTCHA
reCAPTCHA is a free CAPTCHA service that helps to digitize books, newspapers and old time radio shows. About 200 million CAPTCHAs are solved by humans around the world every day. In each case, roughly...
View ArticleConfident Captcha
Confident Technologies provides free CAPTCHA security software called Confident CAPTCHA, a picture CAPTCHA that stops spam and bots. Download our free CAPTCHA security software today.
View ArticleCleanTalk
Spam protection plugins for Joomla, WordPress, phpBB3, IP.Board, vBulletin and etc. Protection without CAPTCHA.
View ArticleUniqPin
UniqPin is a free for non-commercial use service which destiny improve ability of interfaces detect a human or a computer operate with it. Surpassing a CAPTCHA solution UniqPin make human...
View ArticlevisualCaptcha
visualCaptcha is a configurable captcha solution, focusing on accessibility & simplicity, whilst maintaining security. It's also localizable and free, open-source, and we encourage customizations...
View ArticleNegative Captcha
A negative captcha has the exact same purpose as your run-of-the-mill image captcha: To keep bots from submitting forms. Image ("positive") captchas do this by implementing a step which only humans can...
View ArticleFunCaptcha
FunCaptcha is a managed CAPTCHA service. It stops automated abuse and keeps human conversion high with fun visual activities that are easy to understand.
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