Earlier quoted context omitted.
The point of the article is that the sale would happen regardless of the ad. Ie showing an ad on Google to someone who types 'Ebay' in the search string is a waste of money - since Ebay shows up as the first natural result anyways.
However, this leads to the other flaw in the argument, where eBay has been the company most famous for abusing Google's ads, and using them in a completely nonsensical way. http://www.searchenginejournal.com/how-not-to-run-a-ppc-camp... I'm sure you've noticed that a search for any noun called forth an ad for eBay. You're enticed to "buy Dog Vomit on eBay" when your dog is sick. And then, even if it was something eBa…
The methodology and findings should be something that advertisers look at and learn from (i.e. that traditional methods of tracking do not always do a good job of showing value) but instead people just like to point fingers and call names