This plugin allows you block content wordpress post for underage readers.
A script which protects the comment form from spam. Does four ways of protection.
"WP-NoSpamUser" is all about blocking potential spammers from registering on your blog.
Protects all email addresses and mailto: links on your blog from email harvesters using rot13 encryption and/or text mode.
Performs a simple but very effective test on all incoming trackbacks in order to stop trackback spam.