Forum Software on Linux

[jim]

Hey all,

A friend of mine was looking into MSN to host a forum.  I caught her in the 
nick of time :), but I would like some Linux based alternatives to offer her.

What your recommendations as far as forum software goes?  There should be 
threading of messages so someone could follow only the conversations they 
were interested in.  Other than that, what else should I look for?

Thanks,
Jim