So, will Carcassonne have the same community as Catan? We can hope. What we do know is that Sierra is supporting Carcassonne with future expansion packs like Inns & Cathedral and The Tower. It'll also be nice to play the game with people offline. Now we're looking forward to expansion packs to Catan and the arrival of Alhambra, which we haven't heard anything about since it was originally announced last year. Catan and Carcassonne are Euro gaming goodness and we don't even care about the irony of having a $400 system to play board games. When you grow up and your friends are scattered to the four corners of the planet, this is a way to bring everyone back together. Plus, being offline playable against friends (unlike Catan), means easy no fuss clean-up after a game in your living room/bedroom/game lair/castle.
Update: GamerTalkHQ got a list of the game's achievements.