Thanks; this is fascinating. My concern is the reduction of the “global” quality of Twitter. Facebook gets tiresome precisely because you’re writing to the same constituency. It also gives people a pass to vent some really questionable views because there is a cap on the voices who can reply. Hence, the double-edged sword to which you refer. As much as Twitter induces bickering, and invites trolling, it produces a kind of community hearing, however imperfectly. If we limit replies we create segmented networks rather than mass media.