No free lunches online, but plenty of threats to privacy

There's no such thing as a free lunch. Milton Friedman said it in the 70s and my slightly skeptical and generally accurate Italian father has told me that for at least as long. Friedman can have the credit for the saying, but Dad gets credit for the applying.

Since the beginning of the Internet, we have been told that we are getting free stuff (songs, articles, videos, entertainment, gigabytes of storage, social connections, etc.). In reality, we have just been paying with a different currency-our private information. Think about it, you have given Facebook your birthdate, hometown, current town, religion, sexual preference, marital status and a daily update of what you like, what you do and who you know. As Javier David points out in a piece for CNBC in a piece about online privacy, we, as consumers, have become slaves to what we were told was free, but in reality comes with massive payments in a very personal and powerful currency.

In other words, everything that is "free" on the internet has a subtle but powerful price tag.

This is something to think about the next time you sign up for a "free" online service or application, like Facebook or Google+. These companies make their money by offering advertisers targeted marketing opportunities, and they are able to offer those opportunities by gathering the personal information that we so readily supply them with in the form of status updates, tagged photos, location check-ins, "likes" and more.

Luckily, you and I are beginning to understand that controlling how our data is disseminated online means that we must be vigilant about reading and understanding the privacy settings and terms and conditions on these websites. Unfortunately, the average consumer (who is not reading articles on this topic like you are) is not so privacy savvy.

Everything from protecting yourself from identity theft to online reputation management hinges on your willingness to accept the fact that there is no such thing as a free lunch – at least not on the internet. The best place to start is by knowing exactly what a company can and will do with your personal information if you choose to use their services.

John Sileo is an online privacy expert and keynote speaker on social media privacy, identity theft and fraud. His clients included the Department of Defense, Pfizer, and Homeland Security. See his recent work on 60 Minutes, Anderson Cooper and Fox Business.