In a way i'm with wolfsbane on this one. if i have a question about realism, i google it. want info on a gun or piece of equipment? check the site of an army that uses it. this is what i do, and it works.
however, some people find google and other search engines to be very tedious and difficult to use. for these people, the board would be nice. also, i can see the board being both abused and ending up having a lot of political discussion on it.