“Besides offering nearly all of its features for free, it scorns advertising, refuses investment, ignores design, and does not innovate. Ordinarily, a company that showed such complete disdain for the normal rules of business would be vulnerable to competition, but craigslist has no serious rivals. The glory of the site is its size and its price. But seen from another angle, craigslist is one of the strangest monopolies in history, where customers are locked in by fees set at zero…”