4M vs 400K is a pretty wide margin. You also tried to compare growth rates which didn't exist. Finally you're also are showing a graph with Tumblr's growth cli

4M vs 400K is a pretty wide margin. You also tried to compare growth rates which didn't exist. Finally you're also are showing a graph with Tumblr's growth climbing and postereous's growth pretty flat. If anything you just reinforced the point that Tumblr is leaving postereous in the dust.