Choose your online friends wisely, for they may one day determine your APR.

As Banks Start Nosing Around Facebook and Twitter, the Wrong Friends Might Just Sink Your Credit | Betabeat 

A new wave of startups is working on algorithms gathering data for banks from the web of associations on the internet known as “the social graph,” in which people are “nodes” connected to each other by “edges.” Banks are already using social media to befriend their customers, and increasingly, their customers’ friends. The specifics are still shaking out, but the gist is that eventually, social media will account for at least the tippy-top of the mountain of data banks keep on their customers.

“There is this concept of ‘birds of a feather flock together,’” said Ken Lin, CEO of the San Francisco-based credit scoring startup Credit Karma. “If you are a profitable customer for a bank, it suggests that a lot of your friends are going to be the same credit profile. So they’ll look through the social network and see if they can identify your friends online and then maybe they send more marketing to them. That definitely exists today.”

And in the last year or so, financial institutions have started exploring ways to use data from Facebook, Twitter and other networks to round out an individual borrower’s risk profile—although most entrepreneurs working on the problem say the technology is three to five years away from mainstream adoption.

“Credit score is a lagging indicator,” said Brett King, a tall, puffy Australian with white blond hair who is the founder of the online-only bank Movenbank and author of BANK 2.0: How Customer Behavior and Technology Will Change the Future of Financial Services. “At best, your credit score is about 60 days behind. What we’re trying to do is look for things that reflect the likelihood of a future default, rather than what’s happened in the past.”