We're going to be making some changes to both the client and server in the coming days to continue to address some stability issues, mostly related to the speed and availability of the Steam API.
This will mean some short down time when we update - usually about 5 minutes at a time.
Changes we are making:
1. Improving the overall availability of the server and reducing the occurrence of network retry dialogs
2. Changes to make the in-game leaderboard more responsive. As a side effect of this the in-game leaderboard will include non-Steam users.
3. Fixing an occasional client-side problem related to scroll bars
For the most part these are changes that should just make the experience smoother, particularly with regard to networking issues.