I read a very interesting article from PC World regarding browswer cookies. What was news to me was that Adobe Flash and SilverLight can both store their own cookies independent of your browser. So even if you clear your browser cookies or have placed restrictions on them, advertisers and other sites can still track you. Given that Flash has so many security holes, I’m pretty much of the mind to disable Flash all the time except for times when you really need to view flash content.
To help eliminate ads and many tracking cookies, I use a hosts file which does a pretty good job, and for free. What I found interesting about the article is link to a tool from Adobe which allows you to change your privacy settings for flash. This applet has a variety of settings. I promptly launched the applet, disabled all cookies, and deleted all existing cookies.
If you value your privacy, take a look at your Flash cookies! You will likely be surprised how many you have.