I've been facing a weird problem. I'm seeing the same ad on all pages of my site. The ad is a promotion for a contest related to my site's topic, but the image ad runs on ALL pages (90+) of my site in all ad formats! I thought this was a temporary problem, but it's been hours since this happened. Doesn't google limit how many times an ad is shown? A user might not be interested in the product or might have already visited the site. Shouldn't be given an opportunity to see new ads?