I played on p.nerd.nu all day today. About an hour ago, it suddenly got really laggy. Whenever I log on now, a very small portion of the world loads. The rest is void. I can sometimes see other players running around in the distance, but I fall if I step into the void. I can "play" for about 2 minutes before getting a connection lost message. I have tried to play on other servers with the same result. Single player still works just fine, however.
Has anybody else had this problem? What is the solution? I have already tried reinstalling minecraft.