Netsplit

Explanation: A netsplit can be encountered on IRC. IRC is a network of IRC servers. Each IRC user is logged on to a different server. If for some reason one IRC server can't handle all the transfers anymore, then it looses connection to all the other irc servers - and so do the people using that irc server. The channel still does exist, but without the users from the splitted server. A sign for a netsplit is, when numerous people suddenly seem to log off at the same time. Netsplit's usually recover themselves after a short period. If you are on a server that splits way, simply connect to a different server and all your chat partners will be back again. Links: How to use IRC