maybe move all the iPhone forums and dump them in IRC 😉
but seriously though - the amount of detail that can be exchanged over IRC compared to the forums is probably about 10x more "in depth". you see conversations where a bunch of people help a user that you just would not see on the forums. its also done in a matter of minutes instead of a matter of hours. when somebody has lost their data, or needs help installing something - that really makes a difference to their experience and improves their view on both IRC and MacRumors.