The ratings take into account the people who watched the ceremony live, along with anyone who watched it on DVR on the same day.
It's possible that more people tuned in this year to see if the always-controversial Seth would say anything to piss people. And as it turns out, he did piss some people off.
Also, ratings for the Oscar ceremony tend to be higher when the big winners are mainstream hits.
This year's Best Picture winner, Argo, has made $129 million and counting in the U.S. box office thus far, whereas last year's winner, The Artist, only grossed $44 million. Wait — so silent movies don't do well at the box office? Who knew!