This caught me completely by surprise. Like many kids from the 70s, I was there when Mork appeared on "Happy Days" and then was almost immediately spun off into his own series "Mork and Mindy". Since it was set in Boulder (I've seen the "house" they lived in) almost every kid in the state watched the show just because of that. Heck, some kids even got rainbow colored suspenders to wear. Not anyone I know, of course...
I lost track of the show after the second season, since they couldn't keep the same format from season to season and I quit caring. I knew Robin wouldn't be on TV that much longer anyway. I liked many of his movies, including POPEYE, which is almost TOO close to the original comic strip.
His humor appealed to me, the rapid fire thought process, and he always made me laugh. To find out he suffered from depression was a shock. I know a bit about depression, I've had three bouts of deep depression myself, and it can take a long time to get out of it. So I can understand that, and I hope that more people will realize it's a real problem.
RIP Robin Williams.