"You’ve got venture capital-backed startups like BuzzFeed boasting about reaching 150 million-plus unique visitors per month. You’ve got the rise of programmatic ad buying making it easier for advertisers to cherry pick select audiences when targeting ads. And then you’ve got ad agencies increasingly funneling budgets to their in-house, more profitable “trading desks” to handle more ad buys. Not to mention the massive clout of social networks like Facebook, Twitter and increasingly Snapchat. Is it any wonder that mid-sized sites are feeling squeezed?"