I've been pulling my hair out for this because I can't figure it out. I want my ad to look like this: but it keeps appearing like this: Does anyone know how to make it always appear like the first picture -- only one ad unit, not two vertically?
I can't see the first picture... but I think it depends on the advertiser. Some might request a full width ad, but most will request the half width. So you may find that sometimes it is how you want and sometimes not...
Oh, gotcha. Didn't think of that. Would there be a way to filter out the advertisers which require less space? I regularly visit a blog and I see that the 468x60 ad always has one instead of two.
The ads are automatic based on your keywords etc. The advertiser can opt out of being listed on your site, and you can opt out of certain advertisers, but you can't do it based on their ad size.
Sometimes in 468X60 horizontal ad format, Google Adsense displays only one ad. I don't think this is just limited to premium publisher.