The U.S. Federal Trade Commission doesn’t think advertisers are doing enough to respect the privacy of consumers online, so it recently proposed the creation of a Do Not Track system for the web that would give consumers the ability to opt out of ad tracking.

There’s just one big challenge: making that happen technically.

There are numerous hurdles that would need to be overcome in making a Do Not Track system a reality. The FTC’s proposal envisions the addition of a “persistent setting” within web browsers which would signal to websites and advertising providers the user’s privacy preferences, but there is an obvious problem with this: websites and advertising providers would be responsible for respecting this setting. Instead of waiting for a more refined concept to emerge, however, browser makers are (not surprisingly) rushing to offer up their own solutions.

Yesterday, Google announced the availability of a Keep My Opt-Outs extension for Chrome. It allows Chrome users to opt out of being tracked by companies that are members of the Network Advertising Initiative (NAI), and keeps them opted out even when they clear their cookies. The NAI, as Google notes, includes the 15 largest ad networks in the world.

Mozilla, on the other hand, is taking a different approach. It’s looking at a Do Not Track HTTP header. Alexander Fowler, Mozilla’s Global Privacy and Public Policy Leader, explained on his blog:

As the first of many steps, we are proposing a feature that allows users to set
a browser preference that will broadcast their desire to opt-out of third party,
advertising-based tracking by transmitting a Do Not Track HTTP header with every
click or page view in Firefox. When the feature is enabled and users turn it on,
web sites will be told by Firefox that a user would like to opt-out of OBA. We
believe the header-based approach has the potential to be better for the web in
the long run because it is a clearer and more universal opt-out mechanism than
cookies or blacklists.

This, of course, suffers from the same disadvantages as the Do Not Track mechanism proposed by the FTC. But Fowler does hit on the disadvantage of Google’s solution: it’s list-based, and thus inherently limited, even if the participating ad networks do serve up a substantial chunk of online ads.

At this stage of the game, it’s safe to say that neither solution is going to be a panacea. Google’s extension only works with Chrome, and it isn’t universal. Mozilla’s would rely on publishers and advertising providers to respect the Do Not Track header. At the end of the day, neither provides consumers with a guarantee that their privacy is being respected, and in fact, consumers will likely have no ability to discern whether or not they’re still being tracked on any given site.

That said, the almost certain ineffectiveness of these early Do Not Track ‘solutions‘ masks the fact that they could very well start to have an impact on the advertising ecosystem. After all, the rise of browser-based Do Not Track mechanisms could cause advertisers to question whether they’re losing online ad targeting capabilities that they often pay a premium for. If they do, publishers may eventually see lower CPMs, hurting their ability to provide free content and services.

What’s unclear in all of this is whether legitimate publishers and advertising providers are really hurting consumers by tracking their online habits. After all, just about everyone is interested in making sure that consumers are being shown ads that are relevant to their interests, demographic profiles, location, etc. From this perspective, the cure (Do Not Track) may be worse than the side effect (ads that are completely irrelevant).