This plugin attempts to take arbitrary posts and comments and transform them into valid XHTML, a standard that describes how web-pages should be writt
Performs a simple but very effective test on all incoming trackbacks in order to stop trackback spam.
WP-LightForm, the prettiest WordPress contact form.
This plugin provides AJAX enabled comments with paging,comment posting and fields validation to your WordPress blog.
This plugin will allow you to check your entire site against the W3C Validator.
WP-Validate collects all the pages on your site and runs them through the W3C’s HTML Validator.
This plugin makes Thickbox CSS compliant.