CTRs may be low, but the post almost ignores impressions, which are much harder to quantify but still having some value[0]. Of course, with the proliferation of small devices, ad plug-ins, and the general 'banner ad blindness' of a population that is increasingly familiar with the Internet, it's all probably still dropping in value.

I disagree with those who assume it's all useless because they've never personally clicked on any ads ("After all it’s a $16 Billion market. Nobody would spend that much money, without any realistic returns"), but the trends are also pretty clear. Sometimes I feel like retargeting is the last great scheme to squeeze more conversion out of the whole model. But there will probably be at least a couple more...

[0]http://econsultancy.com/us/blog/10487-view-through-attributi...