Google Talk may have a spartan user interface and a small user base, but sometime in the near future, ICQ and AIM will be able to communicate directly with GTalk servers as well. That means that all the XMPP networks can mingle with the millions of ICQ/AIM users, and the federated love-in I was hoping for is one step closer to reality.
Oahh there... Just because AIM/AOL will open up federation to Google Talk, that federation is not transitive. I cannot route my XMPP traffic from my personal domain via Google Talk network.
AIM already has federation deals that you can sign with them, but they are pretty expensive.
Having said that, I would love to see the XMPP world gaining 50+ million new JIDs…