Fair question.
One of our problems in general is that we also use the web as our data source for a lot of things (in addition to our URL index). And there is a bunch of data that can be useful for freshness or goodness signals on those pages that isn’t anywhere else. From a forum’s point of view, it’s primarily just going to let us better understand the authors of the content in the forum, because it’s costly to stick all that information on every post. The hope would be that it would be that it would help promote the best authors and content on the site better and with more freshness. But you raise a good point that the ROI is less obvious than on discussion pages. I’ll raise that issue with others at Google.