From: "This past weekend, thanks to Android users around the world, Android Market exceeded 10 billion app downloads - with a growth rate of one billion app do

From: "This past weekend, thanks to Android users around the world, Android Market exceeded 10 billion app downloads - with a growth rate of one billion app downloads per month" I think it's pretty obvious that the graph is cumulative. They do mention the rate is accelerating, and a cursory glance at the graph tells that the delta between months appears to be increasing as well. I agree, though, that complementing it with a non-cumulative, per-month graph would be informative and interesting.