WOT Firefox Addon selling user data
ndr.de
ndr.de
One day out of nowhere I started seeing obvious non Google ads in my Google searches. Took me forever to realize some QR generator I downloaded years ago was injected them after the page load.
Tried looking up the add-on within the chrome marketplace and the plugin was no longer listed.
Turns out the developers executed a common path of creating a legit plugin then after a large userbase has been established, push an update containing ad injecting code and de-list themselves from the marketplace. Very shady.
Edit: Found http://www.ghacks.net/2016/11/01/browsing-history-sold/, so nevermind (unless you think that's not an accurate portrayal of the German article).