More than 600 Porto city buses and taxis have been fitted with routers to provide free Wi-Fi service. It's being touted as the biggest Wi-Fi-in-motion network in the world. Sérgio Rodrigues/Veniam hide caption

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The sun sets as a visitor uses his mobile phone Monday during the opening day of the 2015 Mobile World Congress in Barcelona. Wall Street Journal reporter Ryan Knutson — interviewed from the conference Monday via Skype by NPR's Robert Siegel — says that for some smartphone users, Wi-Fi may be able to replace most of the functionality of a cellphone carrier. Josep Lago/AFP/Getty Images hide caption

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A man takes a "selfie" while waiting in line to cast his vote in the Wisconsin gubernatorial race in November. Darren Hauck/Getty Images hide caption

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At the start of a meeting to decide the issue of net neutrality, Federal Communications Commission Chairman Tom Wheeler (center) holds hands with FCC Commissioners Mignon Clyburn (left) and Jessica Rosenworcel at the FCC headquarters Thursday. Mark Wilson/Getty Images hide caption

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T-Mobile CEO John Legere pitches a plan that allows unlimited music streaming without additional data charges. Some net neutrality proponents want the FCC to limit plans like these; the commission says it will review them on a case-by-case basis. Ted S. Warren/AP hide caption

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With the technology to conduct more nuanced tests, some companies say they can provide more useful detail about how people think in dynamic situations. Marcus Butt/Getty Images/Ikon Images hide caption

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President Obama, joined by Homeland Security Secretary Jeh Johnson (left), delivers remarks at the National Cybersecurity and Communications Integration Center on Jan. 13 in Arlington, Va. Obama discussed efforts to improve the government's ability to collaborate with industry to combat cyber threats. Kristoffer Tripplaar-Pool/Getty Images hide caption

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Some colleges and police departments are starting to use software that scans social media to identify local threats, but most tips still come from members of the public. Ikon Images/Getty Images hide caption

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