Referencing objects isn't a problem since dnode doesn't do replication, it just makes copies, but referencing functions when the client disconnects can occasionally be bothersome. You do get a hook when the client disconnects:

    conn.on('end', fn)

so that helps. At browserling.com all of our backend and frontend spanning lots of processes over several servers is tied together with dnode, and we haven't had any big problems tracking references that I can think of.