The Player Feed is a Facebook application installed in the usual way. It uses your my.lotro account information to keep track of your characters as you choose, giving you a series of checkboxes to control which servers, characters, and achievements you want to display. It lets your friends know when you log on and log off -- everything after that is up to you. (To prevent the Player Feed from spamming Facebook every time you switch characters, it will wait for a short period of time after you log out to send that notification.)
Check out the post on the LotRO site for all the details.
