Freenode, the IRC server used by the AMRN for chat, has been hijacked. It's highly likely that your password for Freenode is now known to the hijackers.
If you use that password anywhere else online, go and change your accounts immediately.
I suggest that the AMRN stop using Freenode entirely. I'm not sure what could be used as a replacement, but it's obvious that Freenode isn't as secure as we all thought. If anyone has suggestions for another place to chat, post them here.