WOT ("web of trust") is a spyware disguised as a website reputation rating tool and was one of Mozilla’s most popular add-ons. It is packaged in Debian as xul-ext-wot.
WOT has been changed by upstream in 2015-04 to pass all complete URLs with an additional user or browser id to their company server. The company sells the data unfiltered and unanonimized to paying customers.
What to do?
Deinstall WOT now:
$ sudo apt remove xul-ext-wot
and restart Firefox/Iceweasel.
Debian will replace the offending package soon with an empty dummy package. See https://bugs.debian.org/842939
https://nakedsecurity.sophos.com/2016/11/09/wot-pulls-browser-extension-after-privacy-failure/ https://www.kuketz-blog.de/wot-addon-wie-ein-browser-addon-seine-nutzer-ausspaeht/ (best article about the issue, in German)