Master thesis: This paper investigates whether social media can influence the landscape of political protests beyond the size and frequency of protest events. Using early adoption of Twitter at the 2007 South by Southwest (SXSW) festival as a plausibly exogenous source of variation in county-level Twitter penetration, I find that Twitter penetration increases protest frequency in the United States substantially. I show that the effect is stronger for protest movements where coordination is more challenging, due to the scale of the coordination problem or when organizational capacities are low. However, these heterogeneous effects are not large enough to imply drastic changes in the protest landscape. I do not find evidence for heterogeneous effects depending on the topic of protest. Finally, I find that Twitter penetration increases the relative frequency of the use of violence or attempts at suppression by non-government groups during protest events. I find evidence suggesting that social media increases violence during protest events by easing coordination among those opposing the protest.