1. Akismet is a spam fighting service that protects millions of WordPress sites from comment and contact form spam.

  2. Mollom is a freemium web service to get rid of spam, unwanted content and fake users on your...

  3. Confident Technologies provides free CAPTCHA security software called Confident CAPTCHA, a picture...

  4. UniqPin is a free for non-commercial use service which destiny improve ability of interfaces detect...