The real problem, the problem that really irks privacy advocates, is not that the data was made public – the problem is that it's being gathered in the first place without our consent. It's being gathered and used in some way to make money off us.
Just what exactly can such a profile tell about you? (Yes, call it what it is, it's a profile.)
Your search history: what interests you, what problems and what fantasies you have. Your IP address: which countries you take your laptop to, which hotels you like to stay at, which companies you visit.
With more and more sites using online analytics services, for example Google Analytics, the data will also include which sites you visit and what exactly you do there. Throw in the tracking capabilities that Google gained with the Doubleclick acquisition, and what they already had with Adwords, and things start to look really scary.
Put all this together and they pretty much have all our life in their computers.
Governments are often accused of being invasive to your privacy, but in most advanced democracies you can at least petition to find out what exactly your country retains about you. On the other hand, the laws governing the gathering and use of personal data by corporations are very seldom enforced, especially when it's about supposedly anonymous information.
I've come to the conclusion that periodically getting rid of offending cookies is the best way to go about things. Let them track me for a couple of weeks or months – but after that my computer should automatically give me a new identity.
This is one of the reasons that I am a firm supporter of updating and scanning your computers EVERYDAY.
When I finish surfing the web I always update and then run AVG = A Very Good anti-virus, MalwareBytes, and I love C-Cleaner = Crap Cleaner–which are all Free by the way. C-Cleaner can be set to remove all tracking cookies, and clean up your registry.
I highly recommend running ALL three! JUST an anti-virus will not catch some of the Trojans, Backdoors, Spyware. MalwareBytes had detected some "privacy INVADERS", that the anti-virus did NOT find. You can download them Free from CNET.com or filehippo.com.