MINNEAPOLIS — Eyes roll when Rabbi Hayim Herring tells his fellow clergy that they should spend an hour a day on Facebook, MySpace and Twitter.

Listeners at his seminars exchange smirks when he says blogging should be considered mandatory. They look aghast when he recommends posting short video clips from their sermons on YouTube.

It's better than the reaction he used to get.

"They used to look at me as if I'd just said a four-letter word," said Herring, the former senior rabbi at Beth El Synagogue in St. Louis Park, Minn., and now the executive director of STAR (Synagogues: Transformation and Renewal).

But in its seven years, the organization has seen more converts to what many call one of the dirtiest words in religion: marketing.

Across the country, religious congregations have turned more to marketing to keep the members they have and attract others to their emptying pews. The Internet and its explosion of social networking sites add entirely new ways to connect on spiritual issues.

But the growing emphasis on new salesmanship tools alarms others, who say the onslaught undermines the idea that spirituality should be a respite from the clamor of commercialism.

"It's considered heresy in some circles," agreed Greg Smith, a research fellow for the Pew Research Center's Forum on Religion & Public Life. "They consider consumerism shallow."

But, Smith said, "Whether they like it or not, religions are being forced to compete for members."

That debate has intensified with this spring's follow-up study of a 2008 survey that found that 44 percent of adult Americans have a different religious affiliation than the one they grew up in. Surprised by so much movement, researchers went back and asked the respondents why.

Along with the expected answers — marriage to a person of a different faith, the arrival of a new minister, disagreement with church rules — came the discovery that people have started to shop for churches the same way they shop for cars. They test-drive sermons and check out the "accessories," which can include everything from the music or children's programs to the co-ed softball team.

"We live in a competitive religious marketplace," said Pew researcher John Smith. "You have to be competitive if you are going to attract and keep members."

More than just bragging rights are at stake. Maintaining membership is critical for church finances, especially at a time of economic distress when contributions are dropping and endowment funds have taken a beating in the stock market.

Electronic marketing is spreading across all religions. In a recent speech, Rajan Zed, president of the Universal Society of Hinduism, urged his religious organizations to use "smart-phones with BlackBerry, iPhone and Symbian."

While they are at it, he suggested, they should check out Flickr, Habbo, hi5, Skyrock, Tagged, Bebo, Netlog, MyHeritage, Odnoklassniki, Sonico and VKontakte.

"Use new technologies to create a dialogue," he said.

The younger generation's reliance on these electronic social networks leaves religious leaders no choice, Herring said. "If you're not out there, there's no chance of your message being heard," he said.

A few years ago, books such as "Selling Out the Church" by Philip Kenneson and James Street and "Shopping for God" by James Twitchell took hard-edged stances against consumerism.

These days, the criticism focuses more on how the marketing is being done. Even the bluntly named Church Marketing Sucks online site (www.churchmarketingsucks.com) limits its lambastes to poor-taste advertising. The bulk of the site offers tips on designing eye-catching Web pages.

Religious leaders are realizing that the rules have changed. Gone are the days when people went to services simply because they were supposed to, said the Rev. Katharine Jefferts Schori, the presiding bishop (top official in the United States) of the Episcopal Church.

"It used to be socially expected that people would go to church," she said. "That's not true with the current generation. We have to find ways to reach them. We have to be willing to try new things."

Some of the fastest-growing congregations — suburban, mostly evangelical Christian megachurches — embraced marketing from the start.

Their success has prompted more-traditional congregations with dwindling memberships to take notice.