In online question and answer (Q&A) communities, people ask questions and share answers at all levels of topic sensitivity. Identity options within these communities range from anonymity to real name. The amount of engagement, and the quality of engagement on Q&A sites may differ depending on the identity options available. In this paper, we investigate the relationship between the amount of engagement, the quality of engagement, and different types of identity by analyzing three Q&A sites with different identity policies. We find that highly sensitive questions are more likely to be asked anonymously. Furthermore, allowing anonymity does not affect answer quality and only has a weak, negative indirect effect on engagement. On the other hand, anonymity leads to more trolling. We suggest online communities provide a way for users to ask highly sensitive questions anonymously and pair this with moderation mechanisms to reduce trolling