Your comments
I agree with being able to add comments seamlessl. Comments really drive people to upload art. Little commendations for contributing to the community is great too as a motivation to comment and discuss art that's uploaded.
This is a great idea, it'll make it easier to see what your friends and followers have shared via the promote button.
Customer support service by UserEcho
Something along the lines of "Recently Promoted" and it will show all the the art the people you follow have promoted.