Looks really interesting but shame it's dependant on https://chrome.google.com/webstore/detail/websecurify/emclbd... which requires "access to your data on all websites"
I'd be really interested to hear more about why the dependency is there and what the interplay between the two extensions and the cloud bit of the service is?
It is worth mentioning though that the link points to a hosted app - not an extension. You do require an extension for this to work but it is very lightweight and rather simple. The extension only provides the ability to send HTTP requests as you see them.