Companies such as Facebook, Yahoo, Google and AOL collect large amounts of information about us as we move about with our phones, or on the web. This information is supposedly anonymized to protect our #privacy
before it is used or sold.
What you think is stripped of any identifiable fragments can provide links to personal data about you: your name, address, mortgage, political views. This is #BigData
. Just how it's done is explored in Going Mobo.