It'd be useful to be able to click the "Growth by Source" categories for a detailed breakdown. For example, if 100 people used the website signup form, which lists did they subscribe to? What are the "Other Apps"? For the "Added by you" category, which lists were added to or created? The graph would be more useful if it could show just organic growth (i.e. not added by me in a big batch upload, which obscures the natural growth rate).