Enough of the desktop. Time to play some games! Almost, anyway. If you enter The World's main menu, then close it and save (0011) without doing anything else, 0x5507 changes from 0x80 to 0xC0. What does it mean, exactly? Not sure.
Before entering The World itself, we can read posts on the board, which can also add items to the keyword list. Time for some diffs (0012-0016)...
The first thread, "System Explanation" seems to map to a 20 byte region from 0x28E4 to 0x28F7. Problem: there are only nineteen posts. Somewhere in the middle, and extra byte got changed, but I'm not sure where. Well, I can come back to it later. Anyway, like the news items, these start as 0x01 and change to 0x03 when you read them.
Might as well map out the other threads on the board, while I'm at it (0017-0024)...
Okay, results time. They all follow the same pattern as above. Worthy of notice: each thread's posts begin at 0x???4 (e.g. 0x2914) and continue from there. I'm guessing there will be quite a few padding bytes in there.
Based on what I know so far, I'm guessing that the region from about 0x2864 to about 0x40E3 is reserved for flags like that. I know for sure that there's a mail item flag at 0x2864 and a board post at 0x348A, but the region is zeroes up to 0x40E3, so that looks like an upper bound. Of course, that's far more bytes than would be needed for this kind of thing, so it's possible that there's other stuff in there, too.
I think that really is everything you can do before playing the game. Next time: The World!