First, it is no longer respecting Do Not Track, which allowed web users to opt out of cross-site tracking on websites that honor the setting. Do Not Track is supported by most major browsers, including Safari, Chrome, Firefox, Opera and Internet Explorer …
Normally, sites that contain advertising drop a cookie on your device to register the fact that you’ve been exposed to a particular ad. If you later visit the site promoted, the site can read that cookie and note that you saw the ad. This helps advertisers measure the effectiveness of ads when users don’t directly click on them.
Cookies are also used the other way around: noting your interests based on cookies dropped by the websites you visit, and then using that data to serve personalized ads.
Selecting the Do Not Track option meant that sites like Twitter would not drop or read these cookies. However, poor adoption means that many ad networks and websites ignore the option, making it very limited in its effectiveness. Twitter said this was the reason for its decision.
While we had hoped that our support for Do Not Track would spur industry adoption, an industry-standard approach to Do Not Track did not materialize.
Second, Twitter is extending the time for which tracking cookies are active, from 10 days to 30 days. Both changes take effect on June 18.
However, you can still switch off ad personalization from this page in the Twitter settings. Twitter has also introduced more granular controls on the same page.
If you’re using the iOS app, tap the gear icon , select Settings and privacy, tap Privacy and safety, and tap Personalization and data.