The Wall Street Journal broke the story that Google and other online advertising companies have been bypassing Apple’s Safari browser’s privacy settings and tracking users as they moved around the web. It applies to use of the browser on mobile devices like iPhones and iPads as well as Macs. Safari is the only browser on Apple mobile devices and the only pre-installed one on Mac. It’s a long story exactly how it worked but essentially it involved signed in members of Google+ who clicked the +1 button on things they saw online. That generally places a tracking cookie on the user when that happens but Safari blocks ad cookies. However, Google’s Double Click ad network had a workaround that let the cookie be placed anyway, says the Journal.
For its part, Google says the Journal got it all wrong. It’s not like that, see, says Google. "The Journal mischaracterizes what happened and why. We used known Safari functionality to provide features that signed-in Google users had enabled. It's important to stress that these advertising cookies do not collect personal information."