But the many millions who watched online are uncounted. Via CNN Money:
More than 80 million people tuned in to see Hillary Clinton and Donald Trump face off, setting a new record in the sixty year history of televised presidential debates. The final numbers are still being tallied by Nielsen. But the debate averaged a total of 80.9 million viewers across 12 of the channels that carried it live.
Nielsen traditionally measures viewers who watch via traditional TV at home. That means people who watched the debate at parties, bars, restaurants, and offices were not counted. Nor does the 80.9 million viewer total include PBS and C-SPAN. Ratings for PBS will be available later Tuesday.
Various live streams on YouTube together registered more than 2.5 million simultaneous viewers. Live streams on other sites also reached millions of people. This means the actual total audience is significantly higher than 80 million.
The first Obama-Romney debate in 2012 averaged 67 million viewers. The debate viewership number to beat was 81 million, set back in 1980, when Jimmy Carter and Ronald Reagan debated just once before the election.
— Swishcraft & BOUNZ! (@swishcraft) September 27, 2016