Hello,

I think the option for integrated shoutboxes would be a good feature.
They could be enabled/disabled via the admin CP, and then by a members cp whether they want to have it displayed or not. (Even just a hide/show feature would work)
Any posts in the shoutbox would rely on the members forum username being used, so if they were abusing it they could recieve a forum wide warning, rather than a shoutbox ban. (Would prevent spam, flaming etc.)
Themed off the forum skin settings too, so it could look different if the admin has set 2 or 3 skins to choose from.