Forum Moderators: martinibuster
I agree. I thought it would be a sure-fire way to increase epc to have a single ad unit. I've tried them all and it seems (for me) that there is little difference up/down whether I have 1, 3 or 4 ads in a block. CTR however is seems best with 4 ads so that is what I stick with 100% of the time. I believe Google says the 4-up ad works best for the most websites too.
What happens is that Google's algorthm works out what ad *might* be the top earning advert based on CTR and bid price. For example, you might have two ads they can show on your site - 1 pays $0.05 per click, and the other pays $1.00 per click.
If Adsense decides that it's likely that the $1.00 per click ad will have a ctr of 1%, whereas the $0.05 per click ad will possibly have a ctr of >20%, then the 5c ad gets shown on the basis they calculate it might be a better earner overall.
Good idea in theory, and for many sites it might work. It's been my experience that the sites google chooses on this basis are made for adsense, scrapers and general junk that simply don't convert on my site. I block them, then adsense shows all the ads for people selling goods and services to my niche, and they *do* convert.
The moral of this is that having a multiple ad block means you are less likely to show mis-targetted junky ads than you would do with a 1 unit button.
