If you travel often, you know that it's hard to socialize at hotels; short of a chance encounter, you'll probably end up drinking at the bar by yourself. MIT and Marriott may have a better solution in store with their Six Degrees app. The mobile software uses LinkedIn to find connections between you and other guests. You'll know if someone is a college alum, works at the same company or shares your love of scotch. Staff can organize events if there are enough people with common interests, and there's even an LED-equipped table that lights up a line between visitors when there's a match.It's still early goings for Six Degrees. Marriott is just beginning to test the app this month, and there could be some necessary refinement before the company launches a pilot project in a dozen locations. Provided everything works out as planned, though, you might just look forward to business trips -- when the entire hotel is a social network, you could have a lot more to do than watch TV reruns in your room.