Hmm, not sure what happened - nothing useful in the logs that I can see. If anyone was online and paying attention when it happened let me know if you noticed anything relevant going on at the time.
I hosted a game on 1.8.1 beta, started it, when it loaded it said disconnected from metaserver or something. Didn't notice anything unusual, aside from the metaserver message which I hadn't seen before.
must have overloaded from how many people were online !