Five people who follow Bing on Twitter have the chance to win a hundred bucks a piece, courtesy of a sweepstakes the search engine is running today only. It’s called the “Friends Don’t Let Friends Decide Alone” Sweepstakes, and appears to be geared at drawing attention to Bing’s recently launched social features.

Given that these feature were largely based upon Facebook integration, it seems a bit strange that the contest is Twitter-based, but whatever.

Bing is asking via Twitter, “What decision can you not make without your friends?” Today, until midnight tonight, followers can simply reply to the question with the hashtag #decisions, and Bing will randomly select 5 winners to win “$100 towards a night out with friends”.

The money will come in the form of a Visa gift card. To be eligible, you have to be a legal resident of the the 50 U.S. states and District of Columbia, and be 18 or older. Microsoft employees, relatives of employees, and employees of subsidiaries are all ineligible.

I’m guessing Microsoft is using the contest to tap into the social community to spark some ideas for how to improve upon its social search integrations. It’s become quite clear that search in general is trending much more in this direction, and with Google upping the ante with its +1 button, Bing is uniquely positioned to get more out of Facebook – the social network that most already use.

The official rules of the contest are here.