Plugins

These browser plugins allow you to extend the functionnality of browsers

• Dejavu: offers high compression of digital images for use on the web
• Netscape Directory: most widely used plugins are listed there

Adware

Immediate Results Guaranteed: The easiest way to instantly get rid of many ads is to install a host file containing the list of all the most common advertising servers out there.
With this file installed, whenever your browser tries to download a page or graphics from any of the servers on that list, it will instead point to your local machine (aka localhost, aka 127.0.0.1) and find nothing (unless you are running a web server on your machine)
For linux, BSD (inc MacOSX) and *nix based operating systems, this file should be appended to your /etc/hosts file. On windows, you can find this file in your system folder.

Spyware

If that is not enough, or if you are infected with adware, popups or other spyware, consider using a better operating system