Based on what I saw last night, I know exactly why it didn't do well. It's not actually a bad movie, it's just disappointing. Albeit somewhat utopian, the concept is rather interesting. The movie simply fell flat.
The author of the book the movie is based on has apparently set up a foundation based on the concept of "paying it forward." You can get some information on the concept at that site.
The movie, however, was definitely not worth staying up an extra 2 hours last night to watch.