OK, advertising is speech, sure (I suppose). But, there's no right to demand that anyone listen to you; I am still free to peel the logo off my car, remove the tag from my shirt, fast-forward past commercials, tear pages out of magazines.

And that's the problem with trying to use protected speech as a defense for advertising: all that does is protect your right to use it; it does not force me to also use it. Once the content is loaded on my browser, on my computer, I have the right to do with it whatever I please -- including automatically block any of the pieces that I don't want.

You're free to have advertising on your site. I'm free to not download any of it. Freedom is great!