While it’s important to listen and respond to user feedback, it’s often a mistake to treat arbitrary or isolated instances as a roadmap for enhancements. This post about lessons from Livejournal reinforces this. The idea is not new (see Jakob Nielsen, for example), but it’s useful to be reminded from time to time. Users are generally better at pointing out and exhibiting their problems than solving them. That’s why listening to their problems and observing their activity is valuable.
However, I think that there is value in communities that aggregate user feedback and requests, such as Dell’s Ideastorm and My Starbucks Idea, both of which leverage Salesforce’s Force.com platform. UserVoice is another service that shows promise for user feedback aggregation.