Empathy is a client built on the Telepathy messaging framework. However, 
without a proper backend (connection manager) installed, it is essentially
useless.

XMPP, as a standardized and unencumbered protocol, is supported by default
through the Gabble (Jabber and GoogleTalk) and Salut (link-local) connection
managers. However, more are available in Fedora which implement other
protocols available for Empathy. They are as follows, listed by their package
name:

* telepathy-butterfly: MSN
* telepathy-haze-mission-control: AIM and MSN, via Haze
* telepathy-idle: IRC
* telepathy-stream-engine: Multimedia streaming

If you wish to us any of these protocols with Empathy, you will need to
install the appropriate package for the connection manager and configure
the account through Empathy's "Accounts" dialog.