Tuesday's swearing-in of President Obama was the most-watched inaugural event at least since Ronald Reagan took office a generation ago, with tens of millions watching on live television and online.
More than 29% of the TV households in the top 56 markets -- which covers roughly 70% of the country -- saw at least some coverage from 10 a.m. to 5 p.m. on a total of 16 broadcast and cable networks, according to early estimates from Nielsen Media Research. (Nationwide, Nielsen counts 114.5 million TV households.)
At press time, Nielsen was still compiling a final figure for total viewership. But the Obama figure could approach 40 million viewers or so. During Obama's swearing-in at noon Eastern time, the three cable news networks alone delivered an audience of 17.1 million, including 8.5 million on CNN.
The first inauguration of President Reagan in 1981 logged a record 41.8 million. The comparable figure for the first inauguration of George W. Bush in 2001 was 29 million.
This year, however, online viewing may have proved a significant factor. Web firm Akamai Technologies estimated that a record 7.7 million mostly live video streams were viewed during the swearing-in ceremony.
Nielsen does not measure viewing in offices, schools and other public locations; therefore, measuring the Web audience will likely grow in importance during such live news events.