"Citizen journalism also has stabilized. Fewer than one in 10 Web users say they have created their own original news or opinion piece, according to Pew, and comment sections on blogs or mainstream media sites, which were supposed to turn the old one-way media model into a two-way street, are often too profane, hateful, or off-point to attract people. Only one in four Web users has left a comment—probably no more than wrote letters to the editor in decades past"
You have already seen this happen to some extent if you were a blogger in the past five years. People don't comment enough and if they do, all they leave behind is rants. The community feel of blogging which initially attracted everyone is probably now lost to Twitter and may move on to something else in the future. But if Wikipedia has to resort to recruiting then things are getting really bad.