Press and hold on any user and you can add a tag. It is incredibly useful for a myriad of reasons. I started implementing a system for sharing/community tags but I didn’t like the implications of having a parallel voting system to the existing one and scrapped it.

Edit: the best part of the feature is that it can link you to why you created the tag. In this case the user in question argued that supporting women’s rights is the same thing as Islamophobia.