The Romney campaign, referencing two studies, says stimulus doesn't work. But a more comprehensive look at the literature leads to a very different conclusion. Thirteen good studies conclude that stimulative policies are effective, while two studies concluded the opposite. The consensus is clear: economists think stimulus works.
The University of Chicago's Loukas Karabarbounis and Brent Neiman have an interesting new working paper documenting how corporations have used their money from 1975 to 2007. The short version: corporations started saving more of their income, and paying less of it out in wages.