"WP SpamShield - WordPress Anti-Spam Plugin!
Powerful and user-friendly WordPress anti-spam plugin
that prevents spam on blog comments, contact forms,
registrations, and everything else.
The All-in-One Anti-Spam Plugin for WordPress – Without
Leading edge WordPress spam defense, with NO CAPTCHAs,
challenge questions or other inconvenience to site
visitors. This plugin works silently in the background,
and simply makes WordPress spam disappear...!"