Jonathan Zittrain, co-founder of the Berkman Center for Internet and Society, says the right to be forgotten online is "a very bad solution to a real problem." Samuel Lahoz/Intelligence Squared U.S. hide caption

itoggle caption Samuel Lahoz/Intelligence Squared U.S.

Using Tor, or The Onion Router, enables users to hide their online activities. Advocates say the network protects the privacy of activists. But prosecutors say it's used extensively by criminals — and is making it harder for law enforcement to do its job. Daniel Acker/Bloomberg via Getty Images hide caption

itoggle caption Daniel Acker/Bloomberg via Getty Images

Facebook says that starting soon, ad targeting will "include information from some of the websites and apps you use," making ads more relevant to users' interests. iStockphoto hide caption

itoggle caption iStockphoto

Legal experts say it's too soon to know the impact of a European court ruling that will require Google to remove some links upon request. Virginia Mayo/AP hide caption

itoggle caption Virginia Mayo/AP

Annmarie Chiarini, whose ex-boyfriend posted private nude photos of her online, has emerged as a leading voice in the movement to pass legislation that criminalizes "revenge porn." Patrick Semansky/AP hide caption

itoggle caption Patrick Semansky/AP

A Google data center in Council Bluffs, Iowa. Even online privacy advocates acknowledge that keeping personal data out of the hands of third parties is virtually impossible today. Connie Zhou/AP hide caption

itoggle caption Connie Zhou/AP

Google, like Facebook, Microsoft and other Internet companies, is concerned that data requests from U.S. surveillance agencies could ultimately damage its reputation in the U.S. and overseas. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images