In last week's journal club we read about a recent paper in Psychological Science with a very clear message: It should be the norm for researchers to post their data upon publication. In the article, the author (Uri Simonsohn) lays out the major reason why he thinks posting data is a good idea: It helps our field catch scientific fraud in action (e.g., fabricated data). Simonsohn details some methods he has used in the past to catch fraud in the paper and on his new blog over at datacolada.org (I'll have mine blended!).
I agree that posting data will make it harder for people to fabricate data. However, my favorite reason to increase norms for posting data has nothing to do with data fabrication.