Maybe I am over-estimating what Facebook Atlas is expected to deliver over the next years... but I think it will be huge. Like mega-huge. One small indicator for that: Openly targeting cookie-based delivery of ads (which basically the entire market does) and comparing it to people-based delivery (where Facebook is the grandmaster and no one can even think about competing). Imagine they will be able to lobby cookies away one day. Chances are not so bad - every normal user hates cookies.