Most startups don’t fail because they can’t build a product. Most startups fail because they can’t get traction. Startup advice tends to be a lot of platitudes repackaged with new buzzwords, but Traction is something else entirely.  As Gabriel Weinberg and Justin Mares learned from their own experiences, building a successful company is hard. For every startup that grows to the point where it can go public or be profitably acquired, hundreds of others sputter and die.  Smart entrepreneurs know t...