(Well, it technically started making waves even before that, as clips and quotes started to run around the internet before the weekend hit.)
More specifically, CBS is choosing to preempt its regular Friday-night plans in order to re-air Oprah with Meghan and Harry: A CBS Primetime Special, which first made a huge splash with viewers on Sunday evening.
The anticipation going into it was about as palpable as it gets for primetime network interviews, and it definitely showed in the ratings stats, which are almost definitely what inspired CBS to make this royally impulsive scheduling call.