Hi Alex,
Thanks for sharing that. It's really useful to know 
Cookie blocker plugins for Firefox include Abine and TACO but there are others. Clearing cookies at the end of every session is the most effective measure. Firefox has a setting to do this for you automatically.
This doesn't stop sites from using invisible images to track you. Another trick is to use social networking site "Like" buttons which contain surveillance software. In other words, if you're logged into Facebook, Google+, etc., every time you land on a page with their "Like" buttons, they know where you've been and may even know what you looked at, clicked on, etc.
If you use a Javascript blocker like NoScript, Google converts links, for example in web searches, into tracking buttons. You can see it by copying the link location (right click) and then pasting the link into a text editor so you can see it. It doesn't look like the link you copied on the web page, does it?
Again, one of the worst offenders is Google who also use LSOs. It's well worth taking the time to change your Flash Player security settings to disallow LSOs altogether. LSOs are more persistent than regular cookies and more difficult to get rid of. They aren't cleared from the browser cache in the normal way.
To clear LSOs and prevent new ones, go to any web page with a Flash app or movie on it. Right click on the Flash window and select: Global settings... > Storage > Block all sites from storing information on this computer > OK. No more LSOs! If you find that you absolutely must have LSOs for some sites (unlikely), you can permit them on a site by site basis instead. You always have the option to delete all LSOs at any time.
Another thing to secure your privacy is to insist on using encrypted connections (HTTPS Everywhere) so that your ISP can't monitor your communications. Additionally, it'll reduce the efficacy of the NSA's surveillance programmes which re-route a lot of web traffic through their own servers. It doesn't stop them but it makes it less convenient for them.
The only secure way to hide you're identity is to use TOR browser and no Flash, Java or Javascript at all: https://www.torproject.org/ (Originally a US Navy project). This is why governments need to step in and legally prohibit this kind of blanket surveillance. Of course, this isn't 100% effective either.
