I have no time for Malcolm Gladwell because the few chapters of Blink I read showed a complete lack of logical thought or use of evidence to support a coherent thesis, but you might be interested in "Weapon of the Strong? Participatory Inequality and the Internet" by Schlozman, Verba, & Brady in the journal Perspectives in Politics. You might need a subscription to read the full thing (although it let me open the PDF without logging in) but the conclusions are summarized in the abstract at http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=7804317 .