So how DID the networks do in covering the Olympics ? For the BBC the praise was unanimous but NBC, heavily criticised on Twitter for tape-delays on major events also did extremely well.
A big surprise for the US network was the large number who knew the results of events before the tape-delayed broadcast started. Even more eye-opening : people who knew the results tended to watch more in prime time, not less.
The California-based San Jose Mercury News said, "The London Olympics may well be remembered as the event that drove home the power of social media -- partly to the chagrin but mostly to the benefit of NBC, which controlled images of the games in the United States," said the paper.
Twitter estimated there were more than 50 million tweets about the Olympics, at 80,000 per minute after Jamaica's Usain Bolt won the gold in the 200-meter sprint.
Facebook saw the number of fans of Olympic athletes soar: American gymnast Gabby Douglas had 14,358 followers on July 27 and 540,174 less than two weeks later.
NBC executives privately anticipated the London games would have a smaller audience than the Beijing Olympics of 2008., said the Mercury News. Instead, the prime-time audience averaged 31.5 million people a night through Friday, up 12 percent from Beijing.
"Maybe a recession-weary world wanted a collective, uplifting experience. But the explosion of social media is the one big change in the media landscape that would explain the increased ratings, said Lee Rainie, director of the Pew Research Center's Internet and American Life Project.
"It was the great unknown," said Mark Lazarus, chairman of NBC Sports. "Every day in social media is a learning experience, not just for us but for every business. Yeah, I think maybe we did underestimate it."
The IOC estimates some 900 million people worldwide saw the Olympics opening ceremony.
"Sports events are inherently social," said Justin Osofsky, Facebook's director of platform partnerships and operations. "We're never fans alone. We root together, celebrate together and sometimes commiserate together."
One out of five Olympic viewers in the U.S. watched more than one screen at the same time, with tablets or smartphones hooked into the Internet or social media, he said.
The hashtag @nbcfail was the mecca for complaints about NBC's decision not to live stream the opening ceremony (a decision reversed for the closing ceremony) . Tom Brokaw's one-hour World War II documentary on the penultimate day of competition was also criticised .
Many critics focused on NBC's decision to hold back each day's marquee events from television to air them on a tape-delayed basis in prime time.
More nuggets from the Mercury News:
* 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.
* 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.
* NBC said people spent an average of 30 minutes on its website, up from less than 12 minutes a visit four years ago.
* NBC viewership among teenagers was up 27 percent from Beijing, with girls accounting for most of the gain. For kids aged two to 11, viewership was up 32 percent.
* n 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 programme their own Olympics. The BBC found that some 88 percent of Britons had watched some of the Olympics.
* Last word: NBC had planned to broadcast the gold-medal Andy Murray final in singles tennis at 9 a.m. in all markets, live on the East Coast and delayed for three hours out West. Instead, the finals were shown live throughout the country. NBC's West Coast ratings were only a third of those in the East.