Remote Clones
Reddit /r/MMORPG AMA with Raph Koster
"One of our pillars is "have fun in a five minute session."
So for example -- you can download your mind into a remote clone to join your friends on a quick arcadey combat session, then rewind to where you were and carry on or log out. You can't transport goods that way, but we don't want to ever get in the way of you playing with your friends.
There are still a LOT of benefits to playing in groups, building parties with coordinated loadouts of skills, and so on. And of course, there's a big emphasis on asynchronous interdependence. It's a player-driven economy. Services and goods are just about all provided by other players. So the many ways to play are tied together by the economy, and that's a very MMO feeling, but it doesn't get in the way of a quick play session."