It usually doesn't work.

Did not work. Kept receiving the same data for every website - even after restarting MFF and PC.

Doesn't work all the time. If you want a more reliable tool, check out the "BuiltWith" extension by garazy.

Bad privacy: it creates a cookie every time you start firefox even if you do not use the addon, why? The code is not open source and the Terms (privacy) are pretty open: " agree to the use and collection of information... used by the company or any of its authorised partners": no thanks!

This Addon send every url you visit to there Server.
You don't have to click on the button for that.
There collect your Browser-History.

Does this add-on send data/query to whatruns.com on every page I browse? Or only when I click its toolbar button?