Congrats to Kelly Garrett for his publication in the April 2011 issue of Human Communication Research entitled "Troubling Consequences of Online Political Rumoring." You can read the abstract here:
http://onlinelibrary.wiley.com/doi/10.1111/j.1468-2958.2010.01401.x/abstract
ADDED BY KELLY:
Scientific American posted a short podcast on the study, too. Entertaining to hear the whole project distilled to 60-seconds.