Excellently put by Jim Revillini

there’s no doubt about that – tagging is a novel approach to information organization. it’s one of the best systems that the web has adopted and until something better comes along, information systems should make use of it.

. . .

vista’s structure is rigid and hermetically sealed in a proprietary JSP/java applet world. it will die once enough educators rally around the fact that you can’t teach every single course the same way online. the membranes of structure need to be breathable and stretchy – in technology terms: extensible.

vista HAS NO METHOD for organizing ideas. you are right, you could create a better education environment with bbpress and a little training. i think mediawiki might even be a more suitable learning environment, although i’m not sure if there is a tagging extension for it yet. if not, it’s GOT to be in the works.