A patent released by the USPTO reveals that Google might use the eye tracker in Google Glass to determine how many times a Google Glass wearer has looked at an ad; the filing itself hints that Google could start charging advertisers based on a "pay per gaze" fee. A server can determine what the Glass wearer is looking at and if it is an advertisement...Source: http://www.phonearena.com/news/Google-patent-allows-Glass-to-track-ad-views_id46528
