Egyptians use their mobile phones to record celebrations in Cairo's Tahrir Square, the epicenter of the popular revolt that drove Hosni Mubarak from power in 2011. Twitter was often used to record happenings during the Arab Spring. Mohammed Abed/AFP/Getty Images hide caption
A screenshot shows how a team would track changes to its rocket project on a Sunglass platform. Sunglass hide caption
The new look of Facebook's News Feed. Facebook hide caption
An image depicts the SatoshiDice website, which exclusively uses Bitcoin, not dollars, for gambling. NPR hide caption
Twitter announced its partnership with Vine, a video-sharing app that posts six-second videos onto a tweet, on Thursday, Jan. 24. Marie McGrory/NPR hide caption
Facebook CEO Mark Zuckerberg speaks at Facebook headquarters in Menlo Park, Calif., on Tuesday. Jeff Chiu/AP hide caption
Why Is Facebook CEO Mark Zuckerberg Smiling? Maybe because someone might be willing to pay $100 to send him a message. Paul Sakuma/AP hide caption
A screenshot of Google Maps on an iPhone. NPR hide caption
Customer review websites like Yelp have exploded in the last few years, but are negative reviewers at risk of inciting the litigious wrath of angry business owners? Richard Vogel/AP hide caption
People wanted by the police in Pottstown, Pa., are displayed on the Pinterest page of a local newspaper. The police department's social media strategy, which aims to get the images of criminals seen by more people, has also been adapted in Philadelphia. Pinterest hide caption
A damaged home rests on one side along the beach in the Belle Harbor section of Queens, N.Y., on Nov. 5 in the wake of Superstorm Sandy. Craig Ruttle/AP hide caption