Why is that the CPM campaigns consistently get about 10X higher CTRs? It seems to me that if I were a company and wanted to brand, I would make a banner that no one would click, but had my name displayed very prominently. Low CTRs mean low payouts. On the other hand if I am paying CPM, clicks cost me nothing so I might as well make a decent clickable banner. . .
It seems to me that if I were a company and wanted to brand
That is the answer to your question. There was very short time where CPC campaigns where being used *actually* in a good manner, but now a days, even big companies are using it just for branding. They don't want click, but just want their banner to appear - so they are not paying anything and still there are thousands of web sites showing their banners.