Here's an example I'd like to share, this is dotabuff.com (game statistics for Dota 2):
You know what; apart from that floating box in the corner right, I’m okay with the rest of the ads. Yes, they’re there, but I can still see all content, so it doesn’t bother me that much.
But like I said, they have to be there on page load, not do this weird thing that causes content to jump around.
More than often, they cause the page to jump down, or hide content, that's when I block them.
Of course, because of some websites doing this, I actively block ads on all websites.