Plugins extend and expand the functionality of WordPress. 37,387 plugins with 902,881,105 total downloads are at your fingertips.
BuddyPress helps you run any kind of social network on your WordPress, with member profiles, activity streams, user groups, messaging, and more.
bbPress is forum software, made the WordPress way.
Your WordPress, Streamlined.
A very fast caching engine for WordPress that produces static html files.
Akismet checks your comments against the Akismet Web service to see if they look like spam or not.
A simple and easy way to test your theme for all the latest WordPress standards and practices. A great theme development tool!