Quite a bit! The various topical sections of this site cover Adventures and adventuring ideas (some ready-to-play, and some ideas for rolling your own), 2300 Artwork, a store where 2300 "mood" and research material can be bought (through Amazon.com), a section on Characters and character aids, Gamemastering tips (including more character aids, new rules, scenario hooks, and other helpful tips), New equipment (many people's favorite category!), an encyclopedia of the lifeforms of 2300, sections devoted to robots, aliens, and the answers to Frequently-asked questions about the game. Other sections cover links to various interesting sites of different types that might be of use to fans of 2300, Life in the 24th Century (general essays on various topics), links to almost all the former members of the now-defunct 2300 Webring, and numerous other 2300 sites, a complete list of 2300 products (including descriptions of each, and with online reprints of many of the magazine articles), sources where they can sometimes be obtained, sections on Starships and Stellar Cartography, Tasks, historical Timelines of the 2300 universe, the Official _2300 Resource_ Archive, and a section on new (and one old!) Weapons for 2300. While some of these sections aren't finished, yet, they collectively contain an amazing amount of detail to add to any Referee's or Player's view of the game.
At the very top of the page, there's information about the dates that various incarnations of this site went up, and how many times it was accessed in each location, What's New here, a general introduction to this site, a Site-wide disclaimer and copyright notice, a brief introduction to 2300 for the totally clueless (but interested), the new and old guestbooks, and (finally), a site rating derived from the entries guests left...
There's quite a bit of material, here, and it would probably take you weeks to read it all! You'll surely find something useful among all these articles, as well as some others that you won't like or agree with. Come on in, take a look around, and stay a spell, stranger! If you're a fan of _2300 AD_, then the time is now... the place is here!