There's no need for "tracking stuff". You get users to hand over data willingly by making it a useful/convenient feature, at least to some. In this case, simply

There's no need for "tracking stuff". You get users to hand over data willingly by making it a useful/convenient feature, at least to some. In this case, simply let users sync their everything[1] to your servers. Now you can do whatever you want with this information. [1] Browsing history, bookmarks, saved passwords, form autofill data, see https://support.google.com/chrome/answer/185277 https://support.google.com/chrome/answer/185277