Staying Private on the New Facebook

Facebook is a personal vault that can contain photos of your firstborn, plans to bring down your government and, occasionally, a record of your indiscretions. It can be scoured by police officers, partners and would-be employers. It can be mined by marketers to show tailored advertisements. And now, with Facebook’s newfangled search tool, it can allow strangers, along with “friends” on Facebook, to discover who you are, what you like and where you go.