Just as important, most buyers complete their research two weeks or more before they actually buy. (In the travel sector, for example, only 23.8% of buyers make a purchase during a research session.)
This data shows why content ads matter to advertisers: Most buyers aren't ready to make a purchase when they look up "widgets" or "Shelbyville hotels" in Google, so AdSense ads provide a second chance to reach those prospects as they learn more about the products or services that they're interested in buying.
[Disclosure statement: I'm an AdSense publisher, so I have a vested interest in your use of content ads. :-)]