This dissertation explores the relationship between social media use and political participation. The three empirical articles contribute to the development of collective action approaches that incorporate social elements, improving the predictive power of these theories. Additionally, the collective action approaches are applied within a virtual environment to take into account society's growing dependence on digital communication technologies. This dissertation focuses on two social media platforms, Facebook and Twitter, and exploits the network structures of these platforms to determine if social pressure motivates participation. I use two data sources to test my hypotheses: a unique dataset composed of public Facebook data and voter registration data from the 2012 US General Election and survey data gathered during the 2011 Egyptian Revolution. I find that the social components of online social media platforms matter: online social pressure has a positive, significant impact on political participation. Platforms that possess strong tie network structures such as Facebook create a greater change in protest participation than platforms that encourage a weak-tie network structure, such as Twitter. This effect is also found with voter turnout: as the social pressure in one's Facebook network increases, an individual is more likely to vote. This effect is strongest for young users of social media; they possess high levels of digital socialization compared to older users.