Unless you are a one-man-shop, you don't need to know everything. You'd typically have a front-end dev, back-end dev, sys admin, etc. Successful startup founde

Unless you are a one-man-shop, you don't need to know everything. You'd typically have a front-end dev, back-end dev, sys admin, etc. Successful startup founders don't possess those skills, they acquire them after they are successful. Twitter was well known for their fail-whale. All huge sites had several overhauls to scale. Virtually no websites fail because of technical reasons. Your biggest scalability risk is that you won't have to.