Great article from AdAge
The brands that really achieve earned media at scale are the ones who relevantly insert themselves into ongoing conversations in a fun or witty way. And if the last year has taught us anything about social, it's that the window of opportunity to enter these discussions will get smaller and smaller.
It just has to be honest, it can't be contrived (or even perceived to be so). Just has to feel organic. The Oreo Superbowl response, is a good example of this.