Plugins extend and expand the functionality of WordPress. 38,574 plugins with 966,262,248 total downloads are at your fingertips.
Akismet checks your comments against the Akismet Web service to see if they look like spam or not.
BuddyPress helps you run any kind of social network on your WordPress, with member profiles, activity streams, user groups, messaging, and more.
A very fast caching engine for WordPress that produces static html files.
Your WordPress, Streamlined.
bbPress is forum software, made the WordPress way.
A simple and easy way to test your theme for all the latest WordPress standards and practices. A great theme development tool!