Suspicious activity can take the form of a person who claims to own a run-of-the-mill business, yet whose transactions might indicate something is awry. That could mean a housekeeper in San Francisco who receives electronic payments from people with IP addresses in Barbados, New York and Nicaragua, said WePay Chief Executive Officer Bill Clerico.

While scouring the Web can help companies combat scams, it can heighten concerns among consumers and privacy advocates who say social-media sites don’t do enough to protect users’ data.

“I think consumers have consistently traded information for convenience,” Bill Ready, CEO of Braintree, said in an interview. “When you start using it to lend and extend credit, that’s where you start getting into privacy concerns.”

Information Sharing

That hasn’t stopped companies from sifting through the swelling reams of publicly available information -- from searching for e-mail addresses on Google Inc. to reading through LexisNexis and other databases that compile evidence of consumers’ online presences.

Facebook and LinkedIn provide software tools that let companies automatically import information from profiles on the social networks, with users’ permission -- something that consumers are allowing more often, opting for the ease of signing into a website through Facebook, for instance, instead of filling out a separate form.

Intuit, the largest seller of personal-finance software and a provider of payments systems, has begun using LinkedIn to help verify the identities of users, whose profiles on the professional-networking site list detailed descriptions of employment history and often include endorsements and recommendations from colleagues.

“There’s definitely enough meat on the bone there,” said Ken Miller, vice president of strategic risk at Intuit, who was also an early employee of PayPal and helped develop that company’s fraud and risk engine.

Grammar Check

Even grammar can indicate something about users, he said, recalling a friend request he received on Facebook from someone who tried to pass himself off as a young American, yet used language that suggested “it’s someone who’s definitely around eastern Europe or Russia,” he said. “There are certainly algorithms you can build around that.”