NEW YORK — In the age of social media, NBC now has millions of television critics who make their opinions known about every aspect of Olympics coverage instantly.

They’ve even set up their own hashtag on Twitter: #nbcfail. The online complaints focused Saturday on NBC’s decision to air the marquee swimming event won by American Ryan Lochte on tape delay in prime time, and Friday on the network not streaming the opening ceremony online. Sunday’s critics started early: people wondering why the U.S. men’s basketball team’s opening game aired on a cable network while women’s cycling was shown on NBC.

The conversation is so active that NBC’s executive producer of the games, Jim Bell, took to Twitter to answer critics and even change the way NBC is doing something in response.

“#nbcfail is filled with a lot of crying and snark and humor, but NBC can actually learn something from it,” said Jeff Jarvis, a media critic who writes the Buzzmachine.com blog.

Complaints about tape delayed coverage are an evergreen with Olympics held on foreign soil. But the London Games are the first with Twitter, Facebook and other social media sites in full flower, in a mobile phone era where people carry computers that instantly deliver news in their pockets. It has amplified the impatience of viewers who want to see events on their large-screen TVs instantly and haven’t been mollified by NBC’s decision to stream the events live online.

James Poniewozik, Time magazine TV critic, tweeted that “NBC tape delay coverage is like the airlines: its interest is in giving you the least satisfactory service you will still come back for.”

That drew a quick response from NBC’s Bell: “You do know that all sports events are being streamed live right?”

“I do, indeed!” replied Poniewozik. “Have enjoyed it. Apparently a lot of folks still prefer watching it on TV.”

NBC says it saves big events for prime-time airing because that is when most viewers are available to watch them and where the network makes the bulk of its advertising revenue. Since prime time on the U.S. East Coast coincides with 1 a.m. London time, there are no events to air live then. NBC representatives noted that there were 39 hours of live events Sunday on NBC and its affiliated networks.

Jonathan Wald, who produces Piers Morgan’s CNN talk show and used to work at NBC, tweeted that “the medal for most Olympic whining goes to everyone who complains about what happens every four years. Tape delay.”

One of those complainers, in fact, was Morgan: He tweeted his disdain Friday for NBC’s decision not to make the opening ceremony available live.

The advent of Twitter makes it seems like there’s a lot of unhappiness when the majority of viewers are watching NBC on tape delay and appear satisfied with it, Wald said in an interview.

NBC can point to television ratings justifying their approach. The Nielsen company said the opening ceremony drew more than 40 million people Friday, the most ever for one of those Olympic events. Saturday’s first night of coverage was seen by 28.7 million, another record, beating every other first night of Olympic competition. In Beijing four years ago, 24 million watched on the corresponding night.

Jarvis said he believes NBC could satisfy fans by, for example, televising events like Lochte’s race live in the afternoon and then repeating it at night. He acknowledges, though, that he’s not the one who’d potentially be risking millions of dollars in advertising revenue if such a decision cut into prime-time viewing.

NBC has tried to “hold on to old media strategies in a new media world,” Jarvis said. “And that’s a mistake.”

Some of the online complaints seem to take special glee in bashing NBC, with a few describing it like an Olympic sport of its own. Some are quite personal, like the CNN producer who tweeted Sunday: “No USA basketball in my hotel room. Why they aren’t putting it on NBC’s main channel is beyond me!”

Bell, in some of his back-and-forth with online critics Sunday, answered one tweeter who described herself as a St. Louis mom and complained about NBC’s “Nightly News” on Saturday airing results of events that hadn’t been shown on the network yet. Bell tweeted that he’d look into it, and shortly after told her that “Nightly News” would announce a “spoiler alert” to tell people to avert their eyes if they didn’t want to see results.

Not everyone online is a critic. On Sunday, the U.S. Olympic sailing team tweeted that it was “by far the greatest sailing TV coverage in Olympic history.”