Tumblr has been an Alexa Top 100 site for a while and is still growing strong. Meanwhile Posterous has about 4 times less uniques. Yet Posterous has everything to win: it’s a Y Combinator company with top-tier investors like Chris Sacca and Mitch Kapor. Its founders are experienced software engineers with computer science degrees from Stanford. How come it’s eating dust from a small startup started by a high school dropout? The answer is as easy as it is counter-intuitive: Tumblr is a New York company and Posterous is a Silicon Valley company. Or, to put it another way: Posterous is an engineered product, while Tumblr is a designed product.
