"We were surprised when this turned up really low levels of people engaging religion and faith online," said PRRI research director Daniel Cox.
Cox said churches face many challenges in connecting with people via social media. Megachurches may reach a large audience through social media, but the majority of Americans attend smaller houses of worship that lack the resources to run social media campaigns, Cox said.
In addition, the millennial generation, which most strongly embraces social media, doesn't attend services as often as older generations.
According to a recent Pew survey, one-third of adults who use the Internet do not use social networking sites. And a significant minority of Americans do not access the Internet.
The survey also found half of Facebook users didn't list their religious affiliation on their profile.
The Rev. Alan Rudnick, pastor of First Baptist Church of Ballston Spa in upstate New York, considers Facebook and Twitter essential for reaching out to his congregation and local community, but said Americans may be reluctant to label themselves for personal spiritual reasons or out of fear of being ostracized.
"Because social media on Facebook and other places is so easily accessed, people are distancing themselves, because organized religion in a lot of circles has a negative connotation," he said.
White evangelicals were much more likely to use social media for religious purposes, though only a minority did so. One in four white evangelicals say they have listened to a sermon online or downloaded a podcast, compared to 6 percent each for Catholics and other Protestants.
The survey also found that 10 percent have taken video or photos with their cell phone during worship, and nearly as many admitted to sending or reading email during services.
The survey of 1,026 American adults has a margin of error of plus or minus 3.5 percentage points.