The official FFIX Game Manual:
http://www.playonline.com/ff11/manual/index.html?loc=en
Examples of information found nowhere in the official FFXI Game Manual:
http://www.playonline.com/pcd/update...d3/detail.html
http://www.playonline.com/pcd/update...A3/detail.html
With Seekers of Adoulin just around the corner, there is the possibility of an influx of new players. Those new players shouldn't be expected to pore through a decade's worth of update notes just to figure out how to play the game.
I note that the Manual is pretty up-to-date with endgame content like Voidwatch, Legion and Meeble Burrows, but the players doing that content are also the ones least likely to be going through the Manual to begin with.