Twitter yesterday announced support for "Do Not Track," immediately implementing it to halt online tracking of users who trigger a setting in their browsers.

The announcement was made by an official with the U.S. Federal Trade Commission (FTC) during a Do Not Track (DNT) event hosted by Mozilla, the maker of Firefox. Mozilla has been a major proponent of the technology.

Twitter itself kept a low profile, saying only, "We applaud the FTC's leadership on DNT," Twitter tweeted from its own corporate account on Thursday.

"Twitter seems to be the one social network that's doing the right thing [on privacy], said Brian Blau, a Gartner research director who specializes in consumer technology. "They've gone out of their way, compared to competitors, to stand up for users' rights."

Do Not Track relies on information in the HTTP header, part of the requests and responses sent and received by a browser as it communicates with a website, to signal that the user does not want to be tracked by online advertisers and sites. If a website or service abides by Do Not Track, it must stop tracking users' movements, usually by discarding a Web cookie that handled the chore.

Twitter did exactly that, according to Jonathan Mayer, one of the two Stanford University researchers who came up with the HTTP header standard.

"It appears Twitter drops its 'pid' cookie (presumably [for] profile ID) when DNT is on," Mayer said yesterday, ironically on Twitter.

Twitter is the first social service to support Do Not Track, the initiative that was first endorsed by the FTC in late 2010.

Like Blau, Mozilla applauded Twitter's decision to jump on the bandwagon. "We're excited that Twitter now supports Do Not Track," said Alex Fowler, who leads privacy and public policies at Mozilla, in a post on the Mozilla site.

Mozilla was the first browser developer to add Do Not Track support; the setting and background HTTP header information was baked into Firefox 4, the version that launched in March 2011, and has remained in all subsequent releases.

Since Mozilla's move, Microsoft's Internet Explorer 9 (IE9) and Apple's Safari have also added Do Not Track. In February, Google, which had long resisted supporting the technology, announced it would add Do Not Track to Chrome this year.

Chrome 19, which launched this week, does not support Do Not Track.

Ironically, alongside the Do Not Track support Twitter announced Thursday, it also kicked off what it called "tailored suggestions," which uses tracking cookies to suggest accounts for new users to follow.

Tailored suggestions, said Twitter, was an "experiment" that it's rolling out in some markets. The setting, found in the Personalization section of a user's account, is turned on by default.