Looking for input on the best approach to having a chat sidebar similar to Facebook's web app. I'd like to display a list of online users so users can chat with each other. However, I was looking to implement a "Follow" system instead of a "Add as Friend" system. Since a friendship is mutual but a follow is one way, would it be proper to allow user A to follow user B and allow user A to chat/visibly see if user B is online?
I know on Pinterest you can message people if you simply follow them (im sure there are some privacy settings). However, I do not believe it shows if they are online?
What would be best approach for something like this?