In December 2009, Google began customizing its search results for all users, and we entered a new era of personalization. With little notice or fanfare, our online experience is changing, as the websites we visit are increasingly...

Eli Pariser is a pioneer in online campaigning. He helped start Avaaz.org, one of the world's largest citizen organizations, and is now President of the five-million member MoveOn.org. He's a Senior Fellow at the Roosevelt Institute. He...