Social graphs can show these things. For example you deadbeat cousin who is a black sheep in the family probably has a very different circle of friends outside

Social graphs can show these things. For example you deadbeat cousin who is a black sheep in the family probably has a very different circle of friends outside of your family than you or most of your family does. As such he could be identified as an out-lier. In fact I would not consider these algorithms worth while if they didn't do that. I doubt this would replace a credit score but it may argument it. Or it might lead to a lender making further inquires. For example if you've been tweeting about how you "hope to blow tens of thousands of dollars in Vegas" it seams reasonable that would make a lender worry about lending you. In the end I don't see these algorithms are very different from a bank in a small town where the manager personally knows everyone in the town.