This lecture so far seems like the mystical missing one that I left at the back of my head but didn't consider it as important to visit until you're already 100+ employees in.
By what Brian says, it seems extremely hard to hire anyone who doesn't have the same culture you're looking for. I say that, because I think of culture as being tightly twisted with your company products. How do you find people with the same cultural values, when they haven't grown with your product idea the same way that you have while building it?
These are just my initial thoughts for now..