The present study clarifies the role of the informational use of media in facilitating citizens' political participation by focusing on three distinctive modes of news experience (i.e., news reading, posting, and endorsing) within the context of online social networking sites (SNSs). The findings show that news posting contributes to greater participation in politics by positively mediating the relationship between the use of SNSs and participatory activities. In contrast, news reading and endorsing were not significantly associated with political participation. In addition, the study found that the indirect effects of SNS use on participation via news posting are highest among those with a high degree of network political expertise and lower among those with an average level of such expertise.