But my issue, and I guess that of many other users, is that ads are mostly a scam. Products that are actually valuable to the buyers don't need aggressive advertising; just announcing that they exist (through unobtrusive ads) is usually enough for the word of mouth to bring in customers.
Advertising companies are one of the best examples of an adage I have - "the only thing necessary for the triumph of evil is for good men to be separated from it by enough layers of abstraction". Ad companies are those layers of abstraction. They will lie, they will spam, they will abuse users and as a CEO who outsourced customer acquisition to them you may never have an accurate picture of just how much crap people are exposed to on your behalf.