If I'm reading that right, 60% of their users give up after the first week, half of those who stick with it give up after another month or two, and then there appears to be continued decline afterwards.

Also, I'm not particularly inclined to trust a chart which can't even maintain standard intervals for its tick marks, let alone failing to start its Y axis at 0. Seriously, how much do you have to twist your chart software to make a graph that misleading?