This gave me the creeps, because it reminded me of the days in City Harvest. The church stood out for two things for me: its emphasis on donating money, and its emphasis on recruiting your friends and family. (There are a few other organisations in Singapore that do that as well.)
In pursuing the latter objective the church employed various tactics, one of which is similar to what Facebook is doing: make it a competition. Reward the evangelistic ones with praise and prizes. It was a game of both carrots and sticks; for example, the church made its members write down a list of friends that they are “committed” to bringing to one of the church’s services and pass it to the cell group leader, ostensibly for the church leadership to “pray” on.
Very effective, very smart, and very scary.