YOU are the product. This is the not-so-secret wisdom that accompanies the inevitable question of how some online ventures can become profitable.

Like the 20th century heyday of television and radio, countless online companies "broadcast" services upon the Internet for free, operating via investment capital and advertising partnerships. The former requires only the eventual return on investment, by any means, while the latter delivers a cut of the profits of active user engagement.

Several of the biggest of Internet names reverse this model, in a sense, by selling the information that you and I broadcast freely. The basic idea is nothing new; since the late 19th Century, leads and mailing lists have stoked the appetites of salespeople for ever more names and numbers. Every new piece of information raises the probability of an additional sale. Every sharpening of focus makes the target that much easier to hit.

Consumers have rarely harnessed the power of their identities. There have been few attempts to establish ownership of one's own data, and to harness it as a personal commodity to hoard or sell as you see fit. Selling one’s personal info piece by piece is like trying to redeem the cash value of a manufacturer’s coupon -- worthless unless you have bulk quantities, and even then you’d be lucky to find any takers (just ask those young entrepreneurs who have tried to trade a coupon for 0.01 cents at their local Safeway).

Our names and birthdays, our likes and interests, these are all bits of data that are worth fractions of a cent (about two-fifths, according to Joel Stein of Time). But companies like Google and Facebook do have bulk quantities. And they spend considerable time finding companies that pay to put the data to its best use.

If you examine what many data mining advertisers think they know about you, all sorts of humorous inaccuracies can come up. Depending on whose ads you believe, I have been both male and female, adolescent and retired, affluent and struggling. Even when useful details are known, the algorithms by which advertisers link me to their products can be laughably off-kilter; LastFM and Ticketmaster have so far utterly failed to sell me music or tickets based on my listening habits -- perhaps targeted advertising can be fought best simply by not being a predictable and shallow person?

I'm sure that, like me, you've also been annoyed by recurring ads for items that you’ve "shopped for." This can be embarrassing, whether it’s because I happen to be writing about something that is not a personal interest (despite what AdSense believes, I have little use for herbal estrogen supplements), or because I’d hoped to keep Christmas presents a secret for a little while longer.

This sort of data is what Google calls “aggregated, non-personally identifiable information,” and it works well enough to be a multibillion dollar business -- but it’s still far too wide of a net for most advertisers, especially when they can buy bullseyes at which to throw far more targeted ads. Peter Barron, Google's Director of External Relations for Europe, the Middle East and Africa, spoke at the UN panel discussion: "Internet Freedom: Promoting Human Rights in the Digital Age."

Social media has additional value because the data is given rather than taken. Despite the recent uproar over Google’s revised privacy policy, Facebook has far more capacity to connect ad partners with your data. Social media in general gives my personal signature to data in the form of filling out profiles, posting status updates, checking in from locations, and simply "liking." And the privacy policies need not be read and understood to provide consent; Facebook, like nearly all websites, assume that you’re granting access to any available data by using their services -- in most cases, this includes simply browsing a website.

Currently, Facebook and mobile devices are the biggest example because of apps. Third-party apps tap into our data -- not simply from the users that agree to share, but from the friends of the users that may not even know that they're being "scraped." When the "Mobile and Other Devices" section of the proposed revisions to the Facebook Terms of Service included exactly this sort of allowance, the outcry was sufficient to cause a drastic rewrite of the Terms -- and the new version now simply reads "a user's friends' data can only be used in the context of the user's experience on your application."

Our information is so publicly available that one of the fastest-growing industries is "reputation management," companies that offer to make you look better online. The most effective and useful of these can guide you in taking back your privacy and sealing previously unknown backdoors to your sensitive info. The majority, however, are basically personal SEO firms, re-arranging your Internet information so that the best comes first... and the worst gets buried under a mountain of redundant nonsense. What was once a channel for "brand rehabilitation" is now of keen interest to anyone who has ever been irresponsible on the 'net -- in other words, anyone at all.

Ironically, the "wild west" days of the Internet were anonymous and safe (as long as you weren't foolish with your details) are gone. Now that the walls are going up around each digital garden, privacy fears are reaching fever pitch. The "invisible bargain" that we make by trading our data to free services like Facebook and mobile apps isn't exactly equitable, but the joke may be on them -- if the day does come when the online reality matches our paranoia, our personal data will no longer be such a rare and precious commodity. In other words, the more often you pay, the more data has been already made available -- and the more you should have to worry about.

But ultimately, it is not the advertisers that should worry us. They are not, by and large, making decisions that affect our lives. It may be creepy to be presented with uncannily accurate offers for goods and services on every site that we visit, but we'll always be faceless potential consumers to them. The real risks to our privacy come from potential employers, financial reviews, insurance assessments, media corporations, and governmental agencies. It's not the companies that want us to buy their products based on who we are, it's those that want to deny us choices -- and freedoms -- based on who we are.