Love the post Chris, though I'm a bit late to commenting on it :)
I don't know how many major papers are doing this, but it's something several college papers are doing, and something Pulitzer Prize-winning journalist John Hassell has been heading up in a big way at the New Jersey Star-Ledger (http://www.theexplodingnewsroom.com/).
Even the trade pub I work at has tentatively been dipping our toes into Facebook!