Targeting is pretty difficult unless you have a well-defined audience or type of content.<p>My site matches office furniture ads against photo tours of office spaces - fairly is easy to see why they would work. StackOverflow attracts a specific type of person so it seems like the targeting is built-in.<p>I don&#x27;t envy a general news site like CNN where you&#x27;re trying to target specific types of people who read CNN as opposed to an industry vertical.