If you always feel like someone is watching you, it could be that you are paranoia is getting the best of you. However, if you and your smartphone are inseparable, that is an entirely different story.
Marketers can pretty much track all your moves these days, and the surveillance tools available to them are increasing. Check out the info-graphic put together by OnlineColleges.com via Mashable to see how it works. It is a real eye opener.