Web tracking tech is so complex today that it's practically impossible not to be tracked. Together with social media site such as Facebook, Twitter, Linkedin, often that means that advertisers not only know your browsing habits, but also your name, phone number, location, who your friends are, down to what you been doing, and they have it stored on their data centers.
Here's a series of 3 great articles on the issue, from Electronic Frontier Foundation.
If you don't want to be tracked, just turning off cookies is useless today. Here's what you have to do:
I should've known, but didn't realize, that this approach is rather stupid since around ≈2004 because i have Flash on. Because Flash's ability to track is far greater than HTTP cookies.
Of course, there are various browser features and plug-ins that block ads, allow HTTP cookie or Flash only for certain sites you choose, and so on. But these again are not convient. You constantly have to fight with upgrades, new setting interfaces, spend hours to find and learn the new setting location in different interface and different browsers and versions. Do that for multiple computers you have.
So, all the privacy warnings by orgs such as Electronic Frontier Foundation or Free Software Foundation are pretty much fringe concerns for average people.
This doesn't mean that most people don't care for privacy, just that it's too complex and too much effort to do anything about it, given the way the web tech are. I'm not sure how this issue can be resolved.
One good solution is to build privacy related issues into the tech itself. EFF has a good article on this:
Mozilla Leads the Way on Do Not Track By Rainey Reitman @ https://www.eff.org/deeplinks/2011/01/mozilla-leads-the-way-on-do-not-track
“Welcome to the new decade: Java is a restricted platform, Google is evil, Apple is a monopoly and Microsoft are the underdogs” — Phil Nash 2010-08-14
Researchers Expose Cunning Online Tracking Service That can't Be Dodged By Ryan Singel. @ http://www.wired.com/epicenter/2011/07/undeletable-cookie/