Analysts believe that social network sites such as Facebook have paved the way work groups that rely on desktop computers, to collaborate together on ideas and projects while on the move. Mobile social networking makes sense because mobile devices are personal and they are taken everywhere, offering the potential for transmission of quick ideas or images.

For example, a business traveller at a conference in an unfamiliar city could be walking past an appealing restaurant. Using mapping and location technologies, the traveller could almost instantly send a quick note to 10 friends in their work group to 'meet here in 15 minutes for a meal'.

The future of mobile social networks was a major topic at the CTIA trade show, which took place in the US this week. Device manufacturers, network operators and social network providers debated how the services will be paid for and by whom, and what steps must be taken to protect user privacy and safety.

Mobile social networks have not been widely adopted in the US, where between 5 and 10 percent of mobile users are participating, said Karsten Weide, an IDC analyst. But Weide said the number of users could easily double in a year, given the amount of interest in the concept by so many industry players. Adding to the reason for optimism, prominent vendors, including Nokia announced a variety of tools at CTIA to help users aggregate social networks into a single interface.

Still, there are limitations, Weide said, including the difficulty of using a mobile phone or smartphone interface to find friends in a social network, to attach information and to send messages. "Even the iPhone interface, as good as it is, isn't ideal for so much navigating," Weide said.

Perhaps the biggest concern is how social networking sites, such as Facebook, Twitter or MySpace will raise revenue by making their applications work on all kinds of phones across a variety of networks.

Weide said he had talked to executives at two major social networking companies, which he would not identify, who expressed concerns over how they would raise revenue and how much revenue wireless carriers would want to share. In addition to sharing revenues, social network providers have to figure out how much of a customer's personal information to share with carriers, and vice versa.

Doubt has also been cast on whether mobile social networks can successfully be supported with revenues from advertising seen by end users. If advertising doesn't support the concept, then carriers and social network providers will probably have to rely on subscription fees. Questions still remain over how much a user would be willing to pay for a subscription, since that fee might be on top of the cost of a user's unlimited monthly data plan.

NEXT PAGE:The challenges mobile social networking faces

"Advertising is challenged" as a way to support mobile social networking, said Paul Rehrig, vice president of business development for Warner Music Group. However, he said that many companies, including those selling music, are likely to have more success selling certain content to mobile device users than has been sold to desktop computer users.

With music, there is great potential for sharing tunes and reviews through mobile social networks, said Mari Joller, director of new services for Virgin Mobile. She said there is great potential for mobile social networking, given the way young wireless users are already flocking to text messaging and relying on social networks from their desktops.

For that group, "we've found that people are terrified of being out of touch," which means a mobile social connection will be ideal, Joller said.

Still, Joller and others said carriers and social networking sites will have to be vigilant to protect privacy and safety, especially of minors who could be the subject of stalkers or who don't want to communicate their location to a former friend. Controls can be built in and should be, she said.

"We have to have controls that say 'Are you sure you want to share your location,' " Joller said. "We have real life examples of somebody stalking through social networks. It's going to take education with growth in the market ... With the youth demographic, there could be some scary situations on our hands."

Weide said mobile social networks "will be a non-starter" if all the parties don't put in plenty of privacy and security controls upfront, especially for young users.

Mobile social networking could lead to many uses that are only now being imagined, analysts said.

Benjamin Mosse, director of mobile products at the Associated Press, said groups of friends could share news stories and offer comments within their group, instead of posting comments directly to a story. And down the road, he said the AP itself could use GPS technology to track what stories are being read in certain cities, post codes or buildings.