MOSCOW — Russia has taken another major step toward restricting its once freewheeling Internet, as President Vladimir V. Putin quietly signed a new law requiring popular online voices to register with the government, a measure that lawyers, Internet pioneers and political activists said Tuesday would give the government a much wider ability to track who said what online.

Mr. Putin’s action on Monday, just weeks after he disparaged the Internet as “a special C.I.A. project,” borrowed a page from the restrictive Internet playbooks of many governments around the world that have been steadily smothering online freedoms they once tolerated.

The idea that the Internet was at best controlled anarchy and beyond any one nation’s control is fading globally amid determined attempts by more and more governments to tame the web. If innovations like Twitter were hailed as recently as the Arab uprisings as the new public square, governments like those in China, Pakistan, Turkey, Iran and now Russia are making it clear that they can deploy their tanks on virtual squares, too.

China, long a pioneer in using sophisticated technology to filter the Internet, has continually tightened censorship. It has banned all major Western online social media sites, including Facebook, Twitter, YouTube and Google, though it seems not to be bothered by Alibaba, its homegrown e-commerce site, which has filed the paperwork for what could be the biggest public stock offering ever.