I've encountered this weird problem: Servers suddenly disconnect (black box with "server disconnected") then disappear from the list - get new list or refresh doesn't help.
This happened on Fun-Zone, DASPRiD's and Corbina in the space of about five minutes at around 21:00 GMT, I stopped connecting to others after that in case it was something to do with me that was causing this (vanilla 1.1.0 linux client), and I couldn't tell whether the servers had just dropped my connection or went down altogether.
They haven't reappeared on the list yet at the time of writing (21:40 GMT)