Marissa Mayer Has Already Made One Big Mistake With Tumblr

Yahoo's $1.1 billion acquisition of Tumblr is already being hailed as a brilliant move, securing a younger Internet demographic and a fertile field for native advertising, an innovative business model where content from brands lives side by side with users' contributions. In buying Tumblr, Yahoo CEO Marissa Mayer made a nod to the company's past missteps in promising to "not screw it up." But in one crucial way, she already has. That $1.1 billion is a lot of shareholder cash. And so Yahoo is pro...