Another interesting Facebook factoid; see the link below the quote below for the weekly top-20-gainers list.
For several weeks now, Windows Live Messenger has been climbing its way through the growth charts. Now the instant messaging app is at the top of our weekly list of fastest Facebook gainers by daily active users, with 334,214 new DAU.
The really impressive point about Live Messenger is that well over half of its total monthly active users are also daily actives. While Facebook has its own built-in messaging system, international users seem to be picking the Windows alternative in large numbers, and using it regularly.