There really seem to be a number of sites incorporating discussion forums (fora?) lately and my original thought was that a forum is so 1990s but when I considered the iBurst blog a little while ago I realised how valuable a good forum can be when used properly. It is really a question of what kind of collaboration and feedback you want to facilitate and which tool is best for that. A forum is great for discussions about a variety of topics, often topics that users themselves want to debate whereas a blog is great for discussions on specific topics, usually set by the posts.
I see great value in the CrunchForums, if anything, because they could prove to be a source of information about new services and products as well as about existing services and products we all love to use or perhaps love to hate.