Absolutely agree! As an individual who has worked in the ad network space it is definitely a quality and in some ways a quantity "inventory" problem. Many advertisers receive inventory that is often "un-related" content according to the ad networks technologies. Meaning a business niche ad buy may get automotive, gaming or other inventory to fill the order which is on many occasions off-target from what the advertiser has purchased. The challenge for online advertisers is how to get the quantity, while maintaining a consistent, unique message to their target audience. Many ad networks use technologies that help publishers "monetize" their inventory and other ad networks buy bulk media from multiple content sites and re-package it to advertisers. The inherent problem with these models is exactly what the author is saying here the quality of the inventory and in many cases the quantity of the targeted inventory.