That's what *I* was originally suggesting. Sort of.

And "backpackable" is maybe a better description than "pocketable" (unless you have Benson-class pockets). Imagine that some young guy plops down on a city bus seat. Your MID is preconfigured to sniff for portable servers, and it suddenly spies one. You check the lobby and see a game you have and enjoy playing. If one is in progress you join. If one is not you request one. Others who have subscribed to notifications for the game being started are alerted that one has begun.

Of course, that was a highly mobile scenario and depends on everyone engaged being just as mobile as the server. Otherwise, the device could instigate ad hoc meetups whereever, whenever. College campuses, parks, airport lobbies, etc.

EDIT: of course planned events are more practical.