Ok, so I have a gripe.
If you're chatting, whether in the chatroom or via private, and have to head off or otherwise want to end the chat, don't leave the other guy hanging on waiting for a reply as you piss off and don't even bother to log off.
He has a life, and may have stuff to do too. If you consented to a dialogue, then surely you have also given tacit consent to certain norms of polite conversation.
Just say you have to head off etc. Or say you're not interested, or that you are late for the world banana eating championship, you're about to do your big number at the Hollywood Bowl or that you ugently have to go sniff the carpet. But leaving someone dangling because you can't be bothered with the courtesy of a reply?
Grumble over.