In a year when TV ratings for the ABC broadcast of the Oscars declined, Nielsen is also reporting drops in some types of social media activity.
Nielsen Twitter TV Ratings showed that a unique audience of 13.02 million viewed tweets about the Oscars this year, a decline from the unique audience of 13.92 million in 2014.
Tweets also declined from 11.16 million in 2014 to about 5.92 million this year.
Overall, there were about 1.4 million unique authors of tweets this year, which produced some 801.3 million impressions.
Nielsen measures relevant U.S. Twitter activity from three hours before an event through three hours after broadcast, local time, to compile its data for unique authors and tweets.
Reach metrics for unique audience and impressions show the audience of relevant tweets from the time when the tweets are sent to the end of the broadcast day at 5 a.m., Nielsen says.