Microsoft and Adobe both provide good quality forums. We recently relooked at the forum for PowerPoint. Forums used to be a popular place for getting free technical support. Users shared their product knowledge with other users in the spirit of neighborhood help. But whether it is the newer avatar of forums like Stack Overflow or the older PhpBB style message boards, forums are not as active as they used to be. Even Google groups have fallen off the radar for most people. All of them generated a lot of email even if you chose to receive a weekly digest. Sheer quantity of feeds made even RSS an overload. Then the spammers made a total mess of the forums. The net result was that a small and helpful community of users disappeared from such forums.
Corporations took these communities for granted and ignored or deleted negative comments. Users too stopped posting much on such forums. Many users saw these forums as a corporate strategy to save product support specialist cost by farming user efforts at supporting their product. All these factors led to sad demise of user supported forums.