Extended uses a smaller web-based application instead of EQ2's full download, and offers both free and optional paid membership content, as well as the option to purchase equipment. It includes access to all the game zones available in the "real" game, including those added in expansions up to "Shadow Odyssey". In other words, everything but the stuff added in "Sentinel's Fate." Find all the confusing details about the membership options after the break, or check the FAQ.
EverQuest 2 Extended is expected to launch in beta form "on or around August 17, 2010." Along with it, UI improvements will be released for the current version of EQ2.