I think pop-up advertisements have to be the worst thing the internet ever created.
My kids downloaded a music-sharing program that has put so much adware and spyware on my computer that I was getting pop-ups when I wasn't even signed on to the internet! I have spent a week now trying to clean up my computer, and I still haven't undone all the damage.
Add to that the fact that this program is designed in such a way that you have to be a genius to figure out how to uninstall it. (well, maybe not a genius, because I finally got it uninstalled)
Even after uninstalling the program, I am still finding remnants of garbage it left on my computer every day. When this program is downloaded, it makes changes to your registry keys. I actually have to go into the registry now and edit it. If you know anything about computers, you know that this is a dangerous thing to do when you have only the limited computer knowledge that I have.
Moral of the story? Be very careful when downloading anything, especially if it is from a music-sharing program from a company with a name that has three A's in it.