Secondary. Blog.pmarca.com: The Pmarca Guide to Startups, part 4: The only thing that matters. This post is all about the only thing that matters for a new startup.
But first, some theory: If you look at a broad cross-section of startups -- say, 30 or 40 or more; enough to screen out the pure flukes and look for patterns -- two obvious facts will jump out at you. First obvious fact: there is an incredibly wide divergence of success -- some of those startups are insanely successful, some highly successful, many somewhat successful, and quite a few of course outright fail.
Second obvious fact: there is an incredibly wide divergence of caliber and quality for the three core elements of each startup -- team, product, and market.