Pixel movement limitations?
If it does not save the map, our buddy Tom should "fix" that. I don't know if that would be a big issue to do tho. The concept seems simple enough. Put as much static elements of the game into the players client, upon log in, do a check for changes, if any, get em, etc...
The server only transmits changes to objects to a client when a specific piece of information about that object has changed. This is known as an "appearance". Additionally, all resources (icons, music) are cached in memory by heuristic, and, of course, on disk for persistence.
1: Does the server send me full appearance info for each tile? Or does it send me the type of each turf and the values that differ from the type's default values?
2: If I take 100 steps east, with each step I'll be informed of 11 new tiles/appearances. If I then take 100 steps west, I'm walking over turfs I've already seen. If the turfs haven't changed, does the server know this and not send me any information?