If you want to talk with other users and the Developers of MediaPortal join the IRC Channel.
You may use a local IRC Client. See IRC Channel for further information on how to set up your local IRC-client.
You may also use WebIRC (WebChat)
WebChat is a service offered by freenode (and only works for freenode). It uses qwebirc, so check there for help on using it.It is similar to browser chat services and offers basic IRC functions, but no local IRC client is required.
Your nick is how people on freenode know you. If you register it, you'll be able to use the same nick over and over. If you don't register, someone else may end up registering the nick you want. If you register and use the same nick, people will begin to know you by reputation. Only registered users will be able to use pm's/querries.
Note: Sometimes it could happen that the registering fails on the first attempt. Wait for the timeout of 900 seconds then try it again.
enter /msg nickserv identify <your-password>