While MySpace and Facebook will have a strong presence in the mobile market, there's room for a variety of companies to thrive, executives from various mobile social networks said during a panel discussion at the EconSM conference.

The social networking giants have placed increased importance on access from cell phones and smartphones, and MySpace said it expects nearly half of its members to access the site via a mobile phone within five years. This would appear to be a very bad sign for startups like Brightkite, MocoSpace, and others that have mobile-focused social networks, but executives said they're optimistic about their chances.

"We haven't seen any change in our growth curve," said MocoSpace CEO Justin Siegel. "If anything, it's raised awareness and underscored the possibility of what mobile can mean to people."

There are about a billion personal computers in the world, but more than 3 billion cell phones, Siegel said. This leaves a lot of room to gain traction in regions where the bigger players haven't latched on, and Jupiter Research estimates there will be more than 600 million mobile social network users by 2012.

Siegel said the different networks can play different roles in consumers' lives. For example, Siegel said when you message someone on MySpace or Facebook, you don't expect an immediate response -- but you do when using a mobile social network. This different use case probably won't change as time goes on, he predicted.

A key differentiator is that companies that started on mobile can better apply the unique aspects the platform provides, said Brightkite CEO Jonathon Linner. This includes things such as the camera for picture sharing, as well as GPS for location information.

Linner said it's easier than ever to derive geographic information from users via GPS chips, cell towers, and Wi-Fi hotspots, and users increasingly want to share information with others despite possible privacy concerns. While the bigger players are likely to integrate location information in their mobile clients, Brightkite didn't appear very concerned.