(Edit: I'm not suggesting such a market doesn't exist -- I'd just like to know what's actually going on. I'd like to know what's "de facto" practice in the industry.)
There are marketplaces to buy and sell consumer data orginally started around credit agencies and direct mail companies, then growing with the browser toolbar industry when Internet Explorer was big - now they're filled with more information than ever before.
http://www.propublica.org/article/everything-we-know-about-w...
When I worked for a direct marketing arm of the agenccy JWT, we had a bunch of "list augementation" services for our clients' customer lists. Back then, they were used to derive and clean contact information, and glean insights into people's psychology via course methods like correlations to their postal code. (This was surprisingly accurate in Canada, but didn't work as well with US ZIP codes.)
That said, I'd love to hear from a modern insider too. I've just extrapolated.
It's not until we welcome advertising (because it's so aligned with our interests, and it alerts us to things we actually want to buy and do), will we get to the point of the fearmongers.
Do I think this article has a valid point? Of course. Do I think marketers have this wizard of Oz-like power to target us using data? Not yet, but they will in the next 15 years.
It's worth remembering that they will have access to your current data in 15 years; being proactive in the protection of your data now will pay off when marketers catch up with the state of the art.
Also, remember that marketers are not the only consumers of this information. Aside from the government, our "anonymous" profiles are being passed to academic institutions as well, and the results of Facebook's experiments on us are being posted in academic journals.
Additionally, there are the insurance agencies as mentioned in the article - you can bet that they're a lot less than 15 years from using this data against you.