If you look at it, another reason not to trust a system like the “Web Of Trust” becomes apparent.
If you count in that you are also sharing your complete browsing history with MyWOT, you know that using such an “add-on” is anything but secure. Besides, where’s the privacy in that?
WOT members rate websites down for using a tracking cookie while at the same time, the “Web Of Trust” add-on is acting like a tracking tool itself. Does “spyware” ring a bell?