Fight of the century!
One shall stand, one shall burn in recycle bin for all eternity!
IRC:
Pros:
Whole* savage community is there.
Does not afk-kick you.
Cons:
No history mode.
Note: There are specialised IRC clients that allow to connect and stay connected to channels. Also you can /join #cn and /join #savage
Shoutbox:
Pros:
Has history mode.
Easy to moderate.
Cons:
Afk kicks you.
Rather limited in people.
Note: Can be a popup.