Facebook's new search tool, Graph, could eventually be a treasure trove for banks.

The engine could be used to pair sales reps with prospects that have shared interests. Facebook's Graph API could help a bank meet Know Your Customer requirements before opening an account (in combination with traditional data sources). The tool could help banks target new customers who are already friends of existing patrons.

"I think there is really strong potential," says Frank Eliason (@FrankEliason), Citi's global director of social media. But banks need to ease into use of Graph, so as not to offend.

Customers, he explains, have to feel their privacy is protected before a bank even thinks about using a new social media search technology.

Indeed, banks have been slow to even make use of Facebook's social network platform. Most banks are using Facebook as a marketing tool, but few view it as a channel that could truly take advantage of the power of Graph.

Earlier this year, the Menlo Park, Calif. social media company announced that it would be rolling out the tool. Graph uses natural language sentences and phrases, rather than just keywords, to find people, photos, places, and interests – including, possibly, a bank.

For instance, you could ask Graph (which sits in the top of a person's profile) to search for, "People named Sarah that like Bank of America and live in Hoboken, New Jersey."

"Now, with this, eventually you can take [your customer service] to a whole new level of understanding," says Eliason. "You can define your customer base, down to some of the most interesting details in things they like or they have an interest in."

Eventually, Graph could be paired with the ability to sign online banking customers in through social login — something most are shying away from, mostly because of evolving federal guidelines. A non-U.S. exception is ING Direct Canada, which lets its customers log in to online banking through Facbook.

"In our new social sharing economy, isn't this tie-in to the social Graph inevitable as most commercial processes are becoming more focused around social channels and associated data?" says Bradley Leimer, vice president of online and mobile strategy at the $3 billion-asset Mechanics Bank in Richmond, Calif., in an email.

While the initial purpose of "Know Your Customer" rules was to identify fraud, mitigate risk and prevent money laundering, Leimer says the concept can and should be applied toward streamlining the process of setting up new accounts and services, he says. "We can provide customer benefit as we move toward simplifying customer experiences," he says.

He believes more banks will leverage Facebook and other social networks.

Already, alternative banking startups such as Moven are doing so. Moven is onboarding customers through Facebook and lets customers make payments through the social site.

"Banks need to engage these new sets of data as the banking model is rapidly changing," Leimer says. However, he also sounds a note of caution. "There must be benefit in using this data to both the financial institution and its customers for it to make sense," he says.