well wiki is generally better idea, because it has usefull content and is released of spamm and trolling. however i think that requirement for wiki , is that it has free content, that means , that anyone can change it. but i have zero experience in wiki
about forum , well , forum so it would remain vital , needs to have discussion going on , and fresh themes and subjects. however , it often goes at expense of quality of discusions. we would have to reconsider , can we gather that much number of MLs who use internet to keep it an edjucating , sourcefull place on web. i would sugest it becomes a general marxist forum , or anti-revisionist one