WordPress

About
WordPress is a content management system primarily designed for blogging. It is available both as a web service and as software that runs on a web server.

Problems

 * There is no way to preview comments; does not seem to be supported even as an option.
 * The comment form does not indicate what markup is acceptable.
 * Comment threading seems to be turned off by default, as many sites do not support it.

Reference

 * Secunia: security vulnerability database
 * Secunia: security vulnerability database

Official

 * home page