This week in class I asked the Professor for his opinion on Google's push to replace the cookie.

The humble cookie (particularly the "third-party" cookie placed by operator of a website you don't visit) is under threat not just from privacy campaigners but also from the continued growth of mobile technology (for which cookies are largely useless).

Critics are wary of Google's attempts to solve a vexing problem for eMarketers everywhere: this may just be one more way Google tightens its grip around the throat of eCommerce.

"Anyone adopting Google's system would also have to bend to whatever terms Google sets in how that technology and the information it surfaces can be used. In this scenario, Google rises from being the biggest card player at the table to owning the casino. The ad tech companies would be playing with Google's chips."

For now though, you don't have to worry: those Zappos ads will continue to chase you around the web.