Gartner recently issued several predictions detailing how companies will use social software in the future. Here’s one that caught my eye: “By 2014, social networking services will replace e-mail as the primary vehicle for interpersonal communications for 20 percent of business users.”

This is a particularly bold statement given the fact that a growing percentage of businesses strictly control how their employees use social network sites at work. Manpower, for example, found that 29% of businesses in the Americas have a formal policy governing social network usage.

Gartner thinks that those barriers will start to fall away as companies integrate internal social networks and realize the value of using both public and private social networks for status updates and to find people within an organization who have the expertise necessary for a project. 20% isn’t a huge number, and so I certainly think this is in the realm of possibility. But it will definitely require businesses to have a more open attitude toward the utility of social networks.

Update: TechCrunch is now reporting that Facebook is preparing to launch a fully featured webmail product called Project Titan, according to a source with knowledge of the product. Facebook has long kept its messaging service static, making only slight improvements over the years. But if Titan — which would have full POP/IMAP support, meaning you could access the mail account when not on Facebook — can even near the functionality of something like Gmail, it certainly makes Gartner’s projection a bit more feasible.