I'm sure there are various tracking networks that track browsing across websites, it is sort of a logical extension. UPS or Fedex could easily build out a big tracking network.
This is trivial to do for a number of feedback/analytics/cdn/socialnetwork companies. Basically, the people who have JS living on large swaths of the web. There are some names you sorta expect (Facebook, Google, Twitter) and other names like Mixpanel, Foresee, Opinionlab, Survey Monkey that might not be as obvious.
It would be pretty easy for a Foresee to deliver a customer profile aligned on verticals in near real-time to clients based on data their network captures from major websites around the world.
It would be pretty easy for a Foresee to deliver a customer profile aligned on verticals in near real-time to clients based on data their network captures from major websites around the world.