Researchers from many different disciplines rely on social media data as a resource. Whereas some platforms explicitly allow data collection, even facilitating it through an API, others explicitly forbid automated or manual collection processes. A current topic of debate within the social computing research community involves the ethical (or even legal) implications of collecting data in ways that violate Terms of Service (TOS). Using a sample of TOS from over one hundred social media sites from around the world, we analyze TOS language and content in order to better understand the landscape of prohibitions on this practice. Our findings show that though these provisions are very common, they are also ambiguous, inconsistent, and lack context. By considering our analysis of the nature of these provisions alongside legal and ethical analysis, we propose that ethical decision-making for data collection should extend beyond TOS and consider contextual factors of the data source and research.