We use multiple methods to examine how individual websites affect political interest (i.e., citizens’ willingness to pay attention to politics at the expense of other endeavors). Our model clarifies necessary conditions for a website to increase political interest. A survey then reveals age-related and site-specific interest changes that are consistent with the model's logic. Respondents of all ages report greater political interest after viewing sites that they rate as effective and efficient than they do after viewing other sites. Age-related interest effects occur because young and old disagree about which sites have these desired attributes. This work makes two contributions: our methods offer a template for understanding the influence of participatory appeals while our finding can help political entrepreneurs engage young adults more effectively.