Boston ? If the National Security Agency is indeed amassing a colossal database of Americans’ phone records, one way to use all that information is in “social network analysis,” a data-mining method that aims to expose previously invisible connections among people.

Social network analysis has gained prominence in business and intelligence circles under the belief that it can yield extraordinary insights, such as the fact that people in disparate organizations have common acquaintances. Companies can buy social networking software to help determine who has the best connections for a particular sales pitch.

So it did not surprise many security analysts to learn Thursday from USA Today that the NSA is applying the technology to billions of phone records.

“Who you’re talking to often matters much more than what you’re saying,” said Bruce Schneier, a computer security expert and author of “Beyond Fear: Thinking Sensibly About Security in an Uncertain World.”

The NSA declined to comment. But several experts said it seemed likely the agency would want to assemble a picture from more than just landline phone records. Other forms of communication, including cell phone calls, e-mails and instant messages, likely are trackable targets as well, at least on international networks if not inside the U.S.

To be sure, monitoring newer communications services is probably more difficult than getting billing records from landline phones.

Among Internet service providers, representatives for AOL LLC said the company complies with individual government subpoenas and court orders but does not have a blanket program for broader sharing of customer data. Microsoft Corp. had “never engaged in the type of activity referenced in these articles,” according to a statement from Scott Charney, its vice president for trustworthy computing. Google Inc. spokesman Steve Langdon said his company does not participate, either.

Yahoo Inc. officials say they comply with subpoenas, but refused to elaborate, saying they cannot comment on specific government interactions.

Privacy activists worry that the government is likely to try to overcome surveillance gaps by making more use of the information it does have – by cross-referencing phone or other records with commercially harvested data.