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“Some of the criticism I think was fair, and we took note of it and learned from it,” Mr. Lazarus said, “but I think in general, a lot of it came from people who weren’t fully aware of all of the things we were doing.”

According to a Pew survey, 76 percent of Americans who watched NBC’s coverage rated it as excellent or good. Nearly 8 in 10 Americans followed some of the Olympics either on TV or in some other fashion, according to the survey, taken Aug. 2 through 5.

NBC live-streamed every competition through its Olympic website, a process that required customers to prove they were cable or satellite customers, and nearly 1 in 10 Americans registered devices. After some early glitches, the streams generally ran smoothly. The streams led many Americans to try things they never had before. Three-quarters of people who streamed the Olympics on their tablets had never played video on those devices before; 83 percent had never done it on smartphones, NBC said. It wasn’t just young people doing it, either.

There were 63.1 million live video streams downloaded, compared to 14 million in Beijing. The total number of video streams downloaded, live or otherwise, was 154 million, double Beijing’s total. NBC said people spent an average of 30 minutes on its website, up from less than 12 minutes a visit four years ago.

NBC was particularly heartened by the enthusiasm for the games shown by young people. Viewership among teenagers was up 27 percent from Beijing, with girls accounting for most of the gain. For children age 2 to 11, viewership was up 32 percent.

In Britain, the BBC received praise for its Olympics coverage, which included 24 extra digital channels showing live competition. It basically gave TV viewers the ability to program their own Olympics, which NBC did only for computer users. The BBC found that about 88 percent of Britons had watched some of the Olympics on their home turf.

The BBC, however, is a public television network funded largely by a $230 annual fee that television viewers provide, while NBC is supported mostly by advertising revenue and makes most of its money through commercials on its prime-time programming.

NBC conducted a few quiet experiments regarding live programming as the games went on. The network had planned to broadcast the gold-medal finals in singles tennis at 9 a.m. in all markets, meaning it would be live on the East Coast and delayed for three hours out West. Instead, the finals were shown live throughout the country. NBC paid a price; its West Coast ratings were just a third of those in the East. A similar approach was taken for the gold medal men’s basketball game that the U.S. won. The network ultimately must decide whether consumer goodwill is worth the revenue loss.

One of the biggest surprises for NBC was the large number of people who knew the results of events before the tape-delayed broadcast started, either because media made that news inescapable or they had sought out the information. Even more eye-opening was that people who knew the results tended to watch more in prime time, not less.

“People like to see athletes coronated,” Mr. Lazarus said.

NBC will see time-difference issues again during its next Olympics broadcast, in Sochi, Russia, in winter 2014.

“Things are going to be different,” Mr. Lazarus said. “I don’t know how different. We’ll take all the lessons from here and apply them. But that does not necessarily mean we will fully change our model.”