Currently, broadband providers can track users unless individuals specifically ask them to stop. The F.C.C. decision, set to take effect in about a year for major providers, has been hotly contested, in part because the rules apply only to internet service providers, or I.S.P.’s. They do not extend to online ad juggernauts like Google and Facebook — web companies that the F.C.C. does not regulate — which has spurred complaints of a double standard.

Companies like Comcast, Verizon and AT&T are only a small portion of the targeted-ad industry, but are seen as having great potential because of their broad view of online habits. Tom Wheeler, the chairman of the F.C.C., has contended, however, that while consumers may choose not to go on Facebook or use Google, they need I.S.P.s to get access to the internet, a view in line with the agency’s classification of broadband providers as utilitylike services.

The rapid rise of new “smart” devices that use broadband services, like thermostats and refrigerators, encouraged the F.C.C. actions. “Who would have ever imagined that what you have in your refrigerator would be information available to AT&T, Comcast or whoever your network provider is?” Mr. Wheeler said in a statement this week.

Innovation in the advertising industry is currently centered on understanding consumer behavior across devices to better place, track and measure ads, said David Cohen, president of North America at Magna Global, a major ad-buying firm.

“Getting a single view of you or me as I go from PC to tablet to mobile to television — that’s a real hot area in the marketing space,” Mr. Cohen said. “The ones who have the best visibility into that today are the big walled gardens, and that’s primarily Google and Facebook.”