I built something like this to scratch an itch at Zapier (both personally and for a few of our customers). I've mulled over releasing it someday for fun. This is a real need because (frighteningly?) a majority of the business world runs on:
* Generated emails
* Spreadsheets
First of all, I realize this stuff can get complex. But I have one major critique: your extractor UI is way way way too complex. It should be outrageously simple. As in, here are your emails, highlight the data you want to extract. It's hard to build, I know, but I have doubts that your average user will sit through this: http://i.imgur.com/5xjy4dS.png.The concept is great though. The landing page is wonderful. Simple, to the point, decent use cases, inside the app has a nice onboarding and great options around exporting, etc... I really dig it.
Best of luck guys!