IRC
From #openttdcoop wiki
IRC (Internet Relay Chat) is used to improve the communication between all players and friends of #openttdcoop.
Channel: #openttdcoop + Server: irc.oftc.net / irc://irc.oftc.net/openttdcoop
If you want to join our community, you will need an IRC client. We therefore recommend one of these clients:
http://konversation.kde.org/ (Linux, KDE)
http://www.xchat.org/ (Many OS'es)
http://bersirc.free2code.net/index.php/home (Microsoft Windows Only)
http://www.hydrairc.com/ (Microsoft Windows Only)
http://www.mirc.com/ (Mircosoft Windows Only - Shareware)
http://colloquy.info/ (Mac OS X)
http://irssi.org/ (Linux, other UNIX)
If you installed the client, connect to the OFTC IRC network. For further details and FAQ see http://www.oftc.net/ .
To join our channel, simply type: /join #openttdcoop, or join via irc://irc.oftc.net/openttdcoop . Be sure to have IRC_Highlighting enabled.