In my opinion, these site behaviors lower the tool's value proposition because signing up for emails about the product doesn't meet the acute need - scraping - that drove a visitor to the site. It might be better to offer site visitors hospitality.
It sounds interesting, but I never got to the point where I could learn that it was a Chrome app or how it worked.
Anyway, this might make a good "Show HN" if you are looking for additional feedback. https://news.ycombinator.com/showhn.html
Good luck.
Chrome app documentation is available here : http://www.datascraping.co/doc/39/chrome-extension It was just in Help center > Documentation
If you've installed the Chrome app, it will automatically take you to the tutorial.