What if you are asked to perform a different kind of fasting - to log out from Facebook for 99 days!Do not fret as this is a challenge set out by a Dutch creative agency Just.Called "99 Days of Freedom", the non-profit initiative asks whether people would be happier without Facebook.It asks users to give up Facebook for a 99-day period, completing anonymous happiness surveys on days 33, 66 and 99.According to Facebook, a user spends an average of 17 minutes a day on the social networking service.For 99 days, it would mean 28 productive hours that can be used to learn some new skill, the agency said."We found that users have at least a 'complicated' relationship with Facebook," Merjin Straathof, art director at Just, was quoted as saying in media reports.Then, after seeing the news of Facebook's controversial emotion study, the agency launched this challenge."We landed on a 99-day period, hoping that such interaction will serve as a support group of sorts," Straathof added.