Have you guys been playing Arena at all? I played my first three games yesterday and have a rating of 1550ish. We'll see if I can maintain that. Played a fourth game to see if I could improve it and got absolutely demolished.
Basically yes. If you play three games in a day in arena you get a rating. If you get rated 7 days (doesn't have to be consecutive) you get placed in a division. At the end of the season, you'll see your rank in your division. Then a new season starts and it starts over I believe.