Apple's new privacy feature will change the web. And not everyone is happy about it

And ATT, which goes one step further in reinforcing users' control over their privacy, has been widely supported by digital rights groups. Once more, therefore, Apple is building up its reputation as a champion of privacy.

"It's a big step. In the coming days, hundreds of millions of people will be made far more aware of the fact that they have the power to not be tracked," Michael Connor, executive director at not-for-profit Open MIC (Open Media and Information Companies Initiative), tells ZDNet.

"Apple exerts extraordinary influence on the mobile phone ecosystem, and this will set the bar for other apps. People will hopefully come to expect that opting in is a choice they have, rather than something that is inflicted."