Pope Benedict XVI still won't let you poke him (he’s not on Facebook), but the pope has offered new praise of the “great opportunity” of social networking sites and invited Christians "to join the network of relationships which the digital era has made possible."

With a caveat: Virtual relationships are no substitute for the real thing, he said.

"It is important always to remember that virtual contact cannot and must not take the place of direct human contact with people at every level of our lives," the pope said in a statement delivered Monday from the Vatican for the Catholic Church's World Day of Communications.

“Entering cyberspace can be a sign of an authentic search for personal encounters with others, provided that attention is paid to avoiding dangers such as enclosing oneself in a sort of parallel existence, or excessive exposure to the virtual world,” he added.

Increasing ubiquity of social networking

This isn't a new message from the pope but comes amid mounting concern from psychologists worldwide about the increasing ubiquity of social networking.

The pope warned as recently as November that the Internet risked increasing a "sense of solitude and disorientation" among "numbed" youths, a finding echoed the 2010 book "The iConnected Parent," cowritten by Barbara Hofer.

"Warnings like this from the pope make people more mindful of how to use technology in ways that enhance our lives rather than deplete them," says Professor Hofer, who teaches psychology at Middlebury College in Vermont.

"One of the big concerns is that college students are so busy on their cellphones, texting, talking to family and friends, e-mailing, Skyping … that there’s very little time left to sit and think and contemplate on what’s been told in class or what’s happening in their own lives. It’s not just a spiritual issue, but one of psychological well-being," says Ms. Hofer.

The Catholic Church dove head-first into social networking in 2009, launching a YouTube channel, Facebook page, applications for the iPhone and iPod Touch, and the website www.pope2you.net to facilitate the pope's impact online. Other religions have taken the same track.

Although the average church in America has about 75 weekly attendants, many of the larger churches today offer digital streaming of their services, says Leith Anderson, president of the National Association of Evangelicals. The digital world, he says, has become an important supplement to physical worship.

Open up your Bible and turn on your cellphone

For example, at Mr. Anderson's Wooddale Church in Eden Prairie, Minn., the congregation is encouraged to turn on their cellphone when the service begins. A number projected at the front of the sanctuary allows parishioners to text questions to the pastor, who answers a few at the end of service.

"There are always naysayers, but younger evangelicals have largely embraced social media," he says, adding that older evangelicals are increasingly streaming services on the Internet when they can't travel to the church. "We have significant numbers of people who are older who are coming to church over the Internet."

In past messages for the World Day of Communications, such as in 2009, the pope has welcomed social networking sites while cautioning that they can also isolate people from real interaction. Unique to this year’s message seemed to be a call for authenticity in the digital world, where it can be easy to hide behind a screen name or online profile.

"In the search for sharing, for 'friends,' there is the challenge to be authentic and faithful, and not give in to the illusion of constructing an artificial public profile for oneself,” the pope said, without mentioning Facebook or Twitter by name.

While social networking sites such as Facebook have facilitated and played an important role for some in their search for authenticity, says Hofer, she agrees the problem of authenticity is a "very big issue for college kids."

And though students once left behind high school friends when they came to college, now they are expected to be in 24-hour communication with hometown friends and family, as well as their new college network of friends.

"It's exhausting," she says.

It's also affecting the way people communicate. The Monitor, in the cover story "Tech Becomes Us," found that "technology may be determining not just how we spend our time: It actually may be 'rewiring' the way we think, how we experience the world around us."