Bump. Their 80 million user number is quite compelling but the graph always confused me. I figured it was just standard 'clip art' and wondered why they'd show a choppy curve - ie if this is supposed to be a user graph (as it suggests) what are those dips - why were there periods of inactivity. It seemed like a poor graphic choice.
However founder/CEO David Lieb helpfully let me know via Jig that he believes in fact it's drawn from real Bump data.
via David: "it's actually real data in the graph. number of items shared via Bump per week I think."
So the question has been answered! And all I'm left wondering is why they used "number of items shared per week" instead of total users to depict their growth cleanly.