How to build a twitter/irc/real-time app
aaronblohowiak: don't forget that the radius of one user is not the radius of another user. so, you and knuth are both near me, but knuth isn't near you. so when i respond to you in the "channel", should he see the updates?  now, if you want to have me join and leave channels based on my proximity to a fixed location, that's a slightly different problem.you could do this all with xmpp.the wireless client reports location to your dispatch server, dispatch server responds with list of MUCs. the client does whatever filtering the user has setup or whatever and initiates the joins to the MUCs (basicly, the channels to use your terminology.)which xmpp server and client libraries, well that's up to you.  ejabberd has a lot of inertia.