When you are logged into your MDL account you have a small green circular icon that is partly on your profile picture to signify you are online. However, for me anyways, there are times when I am online and logged in (not just MDL but social media as other examples), but I either don't want to be disturbed as I am concentrating on other things or I may only be logged on because I have forgotten to have logged out or I might have logged in but I'd only be on for a very short amount of time.
Anyways, it would be nice if users had the chance to let other users know about their availability - if they are busy (signals their replies etc. may be slower than normal), if they are away from keyboard, if they are logged in but busy watching a drama/movie on MDL or externally, or, if anti-social people want, they could have the option to appear offline. The different colour icons could be as follows:
Green icon - Online
Red icon - Busy
Orange icon - Away from keyboard
Purple icon - watching trailer/video/reading article on MDL
Black icon - watching drama/movie etc. externally (e.g for people who log into MDL but are watching a drama on Netflix)
Nothing - Offline (or 'appearing offline')
Edit: this would also be cool if the purple icon could be automatic but I'm thinking that would be tricky to accomplish