'I Know Who You Are and I Saw What You Did' by Lori Andrews

From the publisher: Social networks, the defining cultural movement of our time, offer many freedoms. But as we work and shop and date over the Web, we are opening ourselves up to intrusive privacy violations by employers, the police, and aggressive data collection companies that sell our information to any and all takers.

Through groundbreaking research, Andrews reveals how routinely colleges reject applicants due to personal information searches, robbers use vacation postings to target homes for break-ins, and lawyers scour our social media for information to use against us in court.