In this paper, we investigate opinion sharing attitudes and behaviors of 13 - 24 year olds on social media platforms. This research utilizes data from 34,514 survey respondents from users of the social media site, myYearbook. Results show that those more engaged with multiple social media platforms are more willing to share opinions, seek opinions, and act on these opinions. However, there were statistically significant differences among users of myYearbook, MySpace, Facebook, and Twitter. Findings show that the reported demographic differences and social network service chosen have an effect on behaviors. These results have implications for businesses and others interested in advertising on these platforms, and researchers interested in investigating these populations.