This chapter investigates the link between young adults' attention to campaign information on offline and online media and their knowledge about political facts and candidate issues. The findings, based on a unique, three-wave panel survey conducted during the 2012 U.S. presidential election, show that attention to campaign information on offline sources, such as television, hard-copy newspapers, and radio, was not significantly related to political knowledge. Instead, young adults' attention to online sources played a more important role. Specifically, political knowledge levels were significantly and positively linked to attention to campaign information in online newspapers and television campaign websites. In contrast, attention to campaign information on social media, particularly Facebook and Google+, was negatively related to political knowledge levels during the fall campaign period. Therefore, this study suggests that certain forms of online media serve as a drain on political knowledge whereas attention to other digital outlets can serve as hubs of information.