Plugins extend and expand the functionality of WordPress. 41,539 plugins with 1,103,213,935 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.
Your WordPress, Simplified.
bbPress is forum software, made the WordPress way.
Akismet checks your comments against the Akismet Web service to see if they look like spam or not.
A very fast caching engine for WordPress that produces static html files.
A simple and easy way to test your theme for all the latest WordPress standards and practices. A great theme development tool!