small chat server?

["Jeremy C. Reed" <reed%reedmedia.net@localhost>]

I have been using yahoo chat for over ten years. But some other users of 
it (that I chat with) often get disconnected and lose conversations.

I'd like to install my own chat server.  I also use jabber/xmpp a lot.

I see that pidgin client supports
    AIM Bonjour Gadu-Gadu Google Talk Groupwise ICQ IRC MSN MXit SILC 
    SIMPLE Sametime XMPP Yahoo! Zephyr

I am not familiar with all these. I'd like some type that offers some 
persistence of conversations, so brief content isn't lost on down 
connections for some hours.

I see various servers under pkgsrc/chat. Any suggestions of a 
lightweight server that supports some common format?  I am looking for a 
very small server install.

Thanks