There is an add-on called AdNauseam. When you enter a page it will randomly click on a few ads for you, but in the background. You won't get to see the ads. Since it always chooses randomly, the advertiser soon get's confused on what products you like....there is just no pattern in all the noise.

Awesome project, and it is banned and blacklisted in Chrome :D

I really like Startpage, was going to include it in this post but decided not to overstretch it and include it in the next one. You are right, it is great!