I am a UX designer, and one of my clients had some questions for me about Google Analytics. His organization has a Facebook page and uses some paid Facebook advertising. The comments on many of his Facebook posts (which promote his new blog articles) come from his site's regular readers.
Using a time scale in the past 30 days, Google Analytics is showing about 72% new users for his site. In the same time period, about 65% of his traffic from Facebook is new users. (If I shorten the time period to just yesterday, it's about 45% from Facebook and 63% from all sources.) Since he expects most of his audience is regular readers, he would like to know: why would Google Analytics be showing so much of his audience as new?
I told him that it's likely to be happening because of some combination of users using private browsing / Do Not Track and cookies not persisting between sessions. But we would like to know if there are any other factors.