Today's ads are even worse than ads used to be (although the worse ads are less common now). These days, you can expect to have to see a full-screen ad or have to watch some sort of video before being allowed to view the content you requested. Then, once you finally get to view the content, you're assaulted with things like Vibrant IntelliTXT and JavaScript that injects content into your clipboard when you copy text.
I don't mind text ads. I don't mind most non-moving image ads, as long as they load fast and aren't too sizeable. Full-screen ads, video ads, flash ads, and JavaScript junk that modify the page contents are the problem here, and they're only getting worse as advertising companies figure out how to abuse our browsers more effectively.