Mozilla added that “Under this partnership, Yahoo will also support Do Not Track (DNT) in Firefox.”

That is a significant change from Yahoo's previous policy. Last April, Yahoo made a point of announcing that it wouldn't even allow Do Not Track requests to be made — which, arguably, was a better (or at least more honest) policy than what it had before: allowing Do Not Track requests, then ignoring them.

Not that Yahoo was or is unique in that regard: most browsers that accept “Do Not Track” requests tend to ignore them. Google Chrome's Do Not Track Page, last updated in October 2012, says this:

Does Chrome provide details of which websites and web services respect Do Not Track requests and how they interpret them?

No. At this time, most web services, including Google's, do not alter their behavior or change their services upon receiving Do Not Track requests.

"Personalized experience"

So in April, when the “Yahoo Privacy Team” updated Yahoo's policy blog, it boasted about making “a personalized experience” for users: “As of today, web browser Do Not Track settings will no longer be enabled on Yahoo. As the first major tech company to implement Do Not Track, we’ve been at the heart of conversations surrounding how to develop the most user-friendly standard. However, we have yet to see a single standard emerge that is effective, easy to use and has been adopted by the broader tech industry. … The privacy of our users is and will continue to be a top priority for us.”

So what happened to change Yahoo's mind about Do Not Track since then? The Do Not Track initiative thus far has (unsurprisingly) proven spectacularly unpopular with advertisers, presumably because they figure that the more data they have on you, the greater their chances of making money thereby.

Last June, an ad-industry trade group called the Digital Advertising Alliance urged a web-standards group to abandon their Do Not Track efforts, for fear that ordinary web users like you and me might be tricked into inadvertently having our online activities not-tracked when we'd actually prefer everything we do be tracked non-stop, or something:

Microsoft, for one, now turns on the do-not-track signal automatically for some Internet Explorer users.

The ad industry says that do-not-track signals set by default don't reflect a user's preference to avoid tracking across Web sites. But the industry also says there's no good way to distinguish between a signal set by a user and one set by a developer.

So, as of last summer, Microsoft's policy set it apart from such companies as Google and Yahoo: they wouldn't honor Do Not Track requests even when they received them, whereas Microsoft made Do Not Track a default setting.

Fast-forward to this month and Mozilla's upcoming changes to its Firefox browser: the Yahoo Search function coming to Firefox is powered by Microsoft Bing. Will Yahoo henceforth honor Do Not Track thanks to a newfound appreciation for user privacy, because they can't avoid it with Microsoft, or for some other reason?

She's inspired

Yahoo CEO Marissa Meyer didn't say one way or other, in her blog post trumpeting the new arrangement between Yahoo and Mozilla, Meyer made no mention of privacy or Do Not Track, but discussed how the new arrangement was sure to be wonderful for Mozilla, Yahoo and all customers thereof, and added:

Our teams worked closely with Mozilla to build a clean, modern, and immersive search experience that will launch first to Firefox’s U.S. users in December and then to all Yahoo users in early 2015. The interactive and integrated experience also better leverages our world-class content and personalization technologies.

Search inspires us because we think it’s something that will change and improve dramatically, and because fundamentally, search is about human curiosity — and that is something that will never be finished.

Google to lose ten-year-old default search status next month