The community platform is a merge between all Atelier 801 games. This merge has two main features, one of them being the possibility to whisper people between different games (e.g. talking to someone playing Bouboum while you're playing Transformice). The other main feature is having a unique account to play in all Atelier 801 games.
The community platform might go down at any moment, but it will be back up within minutes, or sometimes hours, all by itself.