There is all kinds of tracking technology out there already. RFIDs, GPSs in cell phones, cookies on computers, swipe strips on credit and debit cards, even some cars have tracking devices. I think that if this technology goes global, it will be mostly used for advertising and data shuffling.
I already find it a little Big Brother-ish that google and facebook edit my viewing. Google does sorting based on previous searches, geography and other modifiers, and tailors searches for each user. Your google search for won't turn up the same thing as mine. The thing I find the most insidious about this, is that it all re-enforces a particular person's world view. It is getting so that unless you go looking for it, it is hard to find an opinion or news program that disagrees with your own. If this technology is used for marketing, each persons world gets smaller. They only see the products, news and advertising that people just like them are interested in. It makes it harder to see difference, much less feel empathy for those who are different. JMHO