Grats on launching. Are the graphs rendered with d3.js or something else?
It'd be like coming out with the best To-Do or Markdown editor app for iOS. :)
If I could make a suggestion, at some point you should create an analytics "gizmo" (or whatever you want to call it) gallery similar to http://bl.ocks.org/. You could even just parse the gist examples in Python and convert them to HTML/CSS/JS yourselves.
It would make it much easier to use and understand what can be done with your service. Not that I'm saying you aren't planning something like that. You already seem to encourage a pluggable approach, and what's easier than just going through a gallery and pressing an "install" button. Suddenly, you don't have to know any Python.
https://bitdeli.com/docs/python-widgets.html
You can also see a preview of all our analytics templates on our GitHub account:
When you sign up, you can use any of these analytics scripts with your data with just a couple of clicks - no coding needed to get started.