The advantage of using tiled maps is because of speed, but it is only useful when underlying data doesn't change too much. At present, most customers must re-render their tile-set when they know something substantial has changed.
Esri should invent a TiledMap service mechanism that does the following :
1. give the existing tile(s) to the client, (asap)
2. the server re-renders the given tiles and compares the 2 bitmaps (look motion detection algo btw 2 bmp)
3. if there is a change, overwrite the new tile
4. next time anyone accesses that tile, he/she gets the updated version.
You could improve this by checking the last modified time of the map tile.
it only re-renders the tiles that are often used, at a specific zoom level.
Regards
Frederic Poliart
fpoliart@esriaustralia.com.au