Web browsers consider limiting how much they track users

It’s often hard to tell which is the Web’s priority: helping you learn about the world or helping the world — and especially advertisers — learn about you. But that balance is beginning to shift, to the delight of consumer advocates and the horror of industry groups.

Browser makers increasingly are embracing privacy controls that could limit the ability of advertisers to track ­users, threatening to undermine business models that now support many popular online services. The development is driven more by market forces than governmental action, as highlighted by the recent announcement that the maker of one of the world’s most popular browsers, Firefox, is experimenting with new restrictions on the use of cookies — bits of computer code that allow companies to monitor users as they move among Web sites. The news has sparked a fervent debate about the economic value of online tracking and the importance of cookies to the smooth functioning of the digital world. On the day of Firefox’s announcement last month, an official from the Interactive Advertising Bureau tweeted that the browser’s maker had launched “a nuclear first strike” against the industry. That prompted fears that Internet companies could respond with more sophisticated tools that would allow tracking to continue or even expand.