This is actually a good idea. I've always liked the idea of tracking other players, and being able to check a fireplace would be pretty neat. Maybe this idea could be expanded on further by implementing some sort of tracking system. There is a rudimentary ability to do this with the "pop-up" grass, letting you know a player is in the area and has crawled through recentley. I don't have any ideas in particular, but maybe someone more creative than I will have something to contribute.