In just one year, Facebook erased any doubts people had about its mobile business, going from near dead-in-the-water to more than 40% of revenue from mobile. They did it not with banners but by moving its newsfeed ads to mobile and erasing the distinction with desktop ads. Facebook's success is not so much that they're social but that the unit makes sense in context, and there's no reason other publishers can't fast-follow.

http://adage.com/article/digital/trend-online-publishers-worry/243553/