What do we really know about the effectiveness of digital advertising?
I do not work for google facebook or any other internet company.  I do however purchase online ads for my law firm. I also tried turning off the ads for a few weeks to disastrous results.<p>I can say the big problem in the examples in this article is the keyword selection.  For example ebay advertising the word ebay to customers who are googling the word ebay is probably fruitless for the most part.  Those people were already looking for ebay and would find it with or without the ad.<p>However if you are a lesser known online auction and you use the keyword "internet auction" or something similar, it would probably help.<p>This article, to me, seems to be more about the importance of experimenting and critically evaluating the data rather than an actual indictment on online marketing.  With online marketing there is no clear answer: what keyword you bid on, how you target, how you write your ad copies, how your competitors are behaving all come into play.  It's difficult for anyone to parse through those factor and really come out definitively as to whether online marketing is effective or ineffective in general.  We can only do the smaller measurements and see if our particular ads are effective for our particular business, which in the end is all any of us who buy ads really care about.