On the Changing Role of Online Forums?

RighteousRaven asks: "I am doing a study on online forums and their place in a changing Internet environment. For the purpose of this study, I am considering that a forum has two roles: a social hub for people with some commonality, and a repository of information related to that commonality. Previously, forums were the best sources of information on the internet, from motorcycle maintenance to videogame modding, you could learn a lot from a forum. However, with Wikis dominating the internet as dense and highly-searchable information repositories, forums are becoming purely social with no utility beyond personal expression or companionship. Can forums exist on a purely social level? What shortcomings endanger the forum's future, and what characteristics have allowed it to survive so far? Why do we need forums in the first place?"