I have a small anecdote to share. I was writing a proxy server sort of thing. It was my first foray into the land of C and network sockets and I was even more of an amateur programmer than I am now. I was wrestling with this bug for a few hours. After stepping away from it for a while and smoking a bowl or two, I came back to it and looked at my code in a different light (it was still garbage, even though I was stoned) and immediately found the bug. Sometimes it's able to give you a different perspective which is extremely useful for squashing bugs. Now, I can't do normal coding all that well while stoned...it's only really useful when you need to step back and think about things a little differently. Anyway, as far as silicon valley goes, it's not really surprising. It's not like pot is a counter culture sort of thing anymore. I would imagine the usage in the tech industry is high, but no higher than the general population. I will leave you with a video of snoop dogg smoking blunts in the twitter office