WordPress, the world's most popular blogging software, has just released WordPress 3.0, codenamed Thelonious — the software's thirteenth release in its history. Beta releases have been available for the last few months, but now it's official. To give an idea of how popular WordPress is, version 2.9 was downloaded 10.3 million times. Among the features listed in the official blog post: a default theme called Twenty Ten (the old default was looking quite dated), a lighter interface, and 1,217 bug fixes.