Twitter today announced a new way of targeting advertisements for its users, including a partnership with three online tracking firms: media6degrees (m6d), Chango, and Adara. This new system will display ads based on your behavior and reading habits, which show up as "Promoted Tweets" or "Promoted Accounts." This is typical of the direction that major online companies are moving. But Twitter has made some praiseworthy design decisions:

1. Twitter will honor your browser's Do Not Track setting by treating it as a "do not collect" signal. In other words, when Do Not Track is enabled, Twitter will not collect your browsing information in order to show targeted ads on Twitter.

2. Twitter is incorporating a setting to completely opt out of targeted ads. Available in your account settings, this prevents Twitter from collecting information about you, such as your browsing habits through advertising firms as well as encrypted email addresses from partners. (This does not opt you out of all advertising on Twitter.)

We think Twitter is setting an important example for the Internet: It is possible to exist in an ecosystem of tailored advertisements and online tracking while also giving users an easy and meaningful opt-out choice. This is in stark contrast to many other advertising and tracking firms, who continue to argue that "do not track" should mean "pretend not to track." Consumer privacy is an issue of control and transparency; you may be perfectly fine with targeted ads, but you should have the ability to know what information companies have about you and the option of saying no. More and more online companies—many of which already have millions of active users—are turning to third parties to manage their advertising schemes. We believe they should follow Twitter's lead in empowering their users and respecting their use of the Do Not Track setting.

Twitter is also linking to each advertising firm's opt-out pages. To make things a bit easier for you, here are the opt-out pages for m6d (clicking this link will automatically opt you out), Chango, and Adara. These companies use cookie-based opt-outs, however, which means they will install an opt-out cookie onto your browser. By practicing good privacy hygiene and clearing your cookies, you will unfortunately be losing the record of your opt-out to these ad targeting services. Opting out also does not mean that your data is removed from these companies' databases; it simply means that they will stop tracking you if your browser has their opt-out cookie. In the future, we hope that Twitter will be using its leverage with these partners to ensure that they, like Twitter, avoid tracking people who have explicitly denied consent to be tracked.

How Twitter's ad targeting works

Twitter's ad targeting program is very similar to Facebook's targeting that we profiled earlier this year, in that it uses two methods: cookie matching and hashed email matching. Unlike Facebook's, however, Twitter has architected their program to comply with the Do Not Track setting and to make it easier to opt out.

Cookie matching: When you visit a website that has an agreement with one of the three advertising firms that are part of Twitter's pilot program, you are sending data via a browser cookie to these firms' databases. The firms use this browsing history—for example, if you recently visited an online clothing store—to create specific advertising profiles for you. Remember: these firms collect such information about you even if you aren't logged into Twitter.

The m6d, Chango, and Adara tracking cookies will be used to predict interests based on sites you've recently visited, and make shopping predictions or otherwise develop targeting criteria. The ad targeting companies communicate the relevant browser cookie ID to Twitter, which will be used to place you in a bin to receive advertisements "tailored" for that user. In return, Twitter reports in aggregate how many impressions and clicks these ads received.

Hashed email matching: If you are a subscriber to a website's mailing list—for example, the online clothing store's weekly newsletter—cryptographic hashes of your email address might be sent to Twitter. If this hash matches Twitter's own hash of your email, Twitter will know to include you in the website's advertisement program (for example, a promoted tweet about the latest deal on those new summer shirts).

How to opt out

Though the opt-out process may be simple, there are a few extra steps you can take to help protect yourself against unwanted online trackers. For more, check out our guide on how to opt out of Twitter's tailored advertisements (and more!).

Once again, we commend Twitter for making this process as simple as possible for its users and for respecting the Do Not Track browser setting. Twitter has shown a commitment to supporting user privacy (including being one of two companies to receive all six stars in our Who Has Your Back report), and we encourage more companies to follow their lead.