So far, the feature is still being tested by developers, but if everything goes according to plan, it will be included in the next version of Mac OS X (Lion) due to be released in the summer.
Of the top four most used browsers - Microsoft's Internet Explorer, Mozilla's Firefox, Google's Chrome and Apple's Safari - Google is the only company that has yet to decide to add a do-not-track tool in its browser.
According to the Wall Street Journal Google says it will still be closely involved in the discussion about whether do-not-track tools should be offered with browsers, which is actually understandable since Google has a major stake in the market of online advertising.
Google's spokesman also pointed out that the company offers an add-on for Chrome called "Keep My Opt-Outs", which lets users request that their data not be used for targeted advertising.
Even if it seems that there is not much point for tools like these - since they only work if online advertising agencies agree to respect do-not-track requests from browsers, and the majority of them haven't yet - I agree that the realization of the idea must start somewhere, and you can bet anything on the fact it would never have started with the advertising agencies.