When you are browsing the Internet these days you probably will not find a place without any kind of pop-ups, junk or advertising and in a company network those things can be very aggravating and harmful for your network and workstations. You can minimize this by utilizing Privoxy and filtering proxy server that out of the box does a great job. The following video demonstrates how to install and perform a initial configuration.
Ubuntu and the maintainers website provide you with further documentation material.
Enjoy the Video Clip