Would there be any advantages of using SSL on a forum? I have a 50% off coupon so I am thinking about buying one
Does your forum software support it? I think it's a little impractical (well, for mine at least), I guess it may differ depending on what kind of forum you run.
I can not imagine why you would need some thing like that for a forum. You would be better of putting that money towards something else to benefit your forum.