Nearly everyone accepts that publishers should be able to measure traffic volumes on their own sites, for instance. But should advertisers be allowed to track how many visitors see or click on their ads?

The industry’s self-regulatory program, for one, does not turn off data collection. Consumers who install an opt-out cookie no longer receive targeted ads from participating companies, but may still be tracked for non-advertising purposes. That doesn’t satisfy privacy watchdogs.

Microsoft Deputy General Counsel Erich Andersen says tracking protection offers a way around this debate since it lets consumers decide what to block. But this approach worries advertisers since it can block ads altogether, even generic ads.

And anyway, with Do Not Track signals in several popular browsers, websites and advertisers need to agree on how to respond, says Jules Polonetsky, director of the Future of Privacy Forum, an industry-backed group. Otherwise, he says, Do Not Track obligations could get defined for them by browsers or government officials.

Equally important for Do Not Track to succeed, the technology must be easy to find and use. If Do Not Track tools are too confusing or involve too much effort, people won’t embrace them, warns Marc Rotenberg, executive director of the Electronic Privacy Information Center. “We can’t expect users to spend a lot of time reconfiguring their browsers,” he says.

Privacy watchdogs are gravitating to Mozilla’s approach as particularly user-friendly. But it presents a different challenge: ensuring websites, advertisers and ad networks respect user requests not to be tracked. While Microsoft’s tracking protection blocks unwanted content — and requires no compliance by Websites and advertisers — a signal in a browser means nothing if it is not honored.

“Without anyone on the other end to recognize it, it’s a tree falling in the woods without anyone to hear it,” says Mike Zaneis, general counsel for the Interactive Advertising Bureau. Zaneis insists the Digital Advertising Alliance offers the best approach since so many Websites and advertisers are on board.

Alex Fowler, Mozilla’s global privacy and public policy leader, says the browser maker is talking with many big websites, advertisers and ad networks about honoring its Do Not Track signal. And many are open to the idea. Still, so far only a handful of industry players have actually pledged to honor the signal.

And that, privacy watchdogs say, shows why the government needs to get involved.

Senator Rockefeller is sponsoring a bill that would direct the FTC to write binding, industry-wide Do Not Track rules. There are similar bills in the House and the California legislature.

The Internet marketing industry wants to head off those efforts and insists it just needs more time to establish meaningful privacy controls.

For now, FTC Chairman Jon Leibowitz is willing to give the industry a chance before calling for legislation. Even without a government mandate, he noted, it’s in the industry’s self-interest to make Do Not Track work. After all, Leibowitz says, “nobody wants to be on the wrong side of consumers.”