Felix Salmon points out that online ads are “easy to ignore, there’s nothing inherently interesting about them, and insofar as they grab your attention, they tend to do so in a very annoying way, by preventing you from reading or watching the thing you were looking for”:

Hence the rise of so-called native ads: things you want to read and look at and click on. There’s a certain amount of promise there, and the native-ad industry is certainly going to grow from its present size. But it’s tough: building these things is a huge amount of work for the advertiser, with no guaranteed payoff. And selling them is even more work for any publisher. And here’s the next big problem with selling online advertising, especially native advertising: it’s really expensive to do so. While online journalism is still cheap, online ad-sales staffers tend to cost a fortune, especially if they have a clue what they’re doing.

He goes on:

I was told this evening that Buzzfeed alone has no fewer than sixty ad-sales people, all of whom are out there, knocking on doors, taking potential clients out to lunch, and generating income one hard-won deal at a time. That doesn’t scale.