Proving that social networks can be used for just about anything, brand marketers in the travel business are turning to the medium as a means of attracting and staying in better contact with their customers.

According to a report in The New York Times, Expedia is planning to launch its own social network later this month to compete with Orbitz, which opened its social network as a means for disseminating flight information and travel tips last fall.

But it's not just leisure travel that's being swept up by the social networking phenomenon. American Express Business Travel announced a partnership with Sabre Travel Networks, which has its own social networking platform known as Cubeless. American Express said it hopes to offer the social network as a means for its business travelers to share information about hotels, restaurants, services and attractions around the world.

As for Orbitz, which has the longest track record in the relatively young travel social networking field, the company has learned a peculiar lesson. According to Tom Russell, Orbitz's VP of brand marketing, the idea over leveraging social networks, "came from insights that the customers trust strangers more than they trust the authority."

That lesson, and the time spent using social networks, may be the two biggest forces driving growth in that sector, and it's why many brands are looking for ways to interject themselves into those conversations. Last month, Visa found its way into the conversation on Facebook by offering $100 of free advertising to users who downloaded the company's application.