Brilliant.org is truly an interesting website for math and physics and also it connects thousands of math lovers worldwide . I guess you have understood what I want to tell just by seeing the title .
Snehal Shekatkar wanted to make friends on Brilliant and to me the ''Follow'' system is half of it . I am telling it half because friends can talk to each other anytime but there are no way of it in Brilliant without solutions or discussions .
I am suggesting making an inbox private only to the user . You may find someone just like you want and the profile isn't enough to know about that user . Again if you face problems you may not feel free to start discussions at all times . So, for sharing , questioning , knowing each other messaging is much better than discussions .
I found a discussion Social Aspect like this . I have started this discussion just to see the support of the users of this time . Let me know your thoughts.......