I learnt something new yesterday which may have been common knowledge to a fair number of people but changed one of the assumptions I had about how the Google Adsense program shows adverts.
We’ve all seen how Adsense can sometimes show only a single advert in a large advert box. So you’ll end up with a skyscraper advert (120×600) which only has a single advert in the entire area in huge text.
Now here’s the thing; I always assumed that this was due to the lack of inventory (that is people who are bidding for the adverts that are listing on your sites keywords) however it turns out that this is actually a feature of Google Adsense where, if an advertiser is bidding well more than the next few bidders, then that advert will take precedence over both of the next adverts and only it will show. This can also happen if a Google Adwords advertiser is specifically targeting adverts to your site.
I can’t say I really like this feature much from a design stand-point as you can end up with some pretty glaringly ugly adverts on your site when you though you were going to have some nice text listings. The main positive is really that this will increase the revenue on your site.