From Compete - yearly change:<p>tumblr: +184.36%<p>posterous: +297.36%<p>So, uh, even with the last 3 months in posterous is still growing faster than tumblr. If it were a stock its valuation would have increased more than tumblr. Also, wouldn't there definitely be less hits to posterous based on the fact that you <i>EMAIL</i> posts in rather than sign in? That being said, the tumblr landing experience is probably one of the reasons I blog with them and not posterous.