One of our favourite Mac apps, AdBlock is a browser extension that filters out advertising on web pages. It can filter out other stuff too, like Facebook and Twitter buttons. The effect of this is hard to imagine but there are pictures on the Adblock website that make it very clear.
Adblock is for Safari (and other browsers) on computers, not mobile devices. This little gem costs as little as you care to pay for it, is easy to install, and works in the background without bothering you at all.