I found a free program called Ghostery that blocks sites from leaving tracking devices on my computer, and I am amazed at how much it's cut down on ads. I don't mind the quilting related ads, but some of the other stuff is annoying, especially when it pops up wherever I go.
Ghostery tells me how many sites it's blocking on every page I go. My son's been to sites where over 20 other sites were trying to track him! No wonder weird ads used to show up!