It was a touching, made-for-television moment. There was the newest American gold medalist, the 17-year-old Missy Franklin, reflecting on her triumph with her parents.

“When you’re 17 years old and win your first gold medal, there’s nobody you’d rather share it with,” the commercial began.

There was only one problem. Her gold-winning race hadn’t been broadcast yet.

NBC, which has endured withering criticism online for its decision not to broadcast Olympic events live, mistakenly showed a preview of a “Today” show segment about Ms. Franklin and her winning sprint in the 100 meter backstroke before televising the actual race on Monday night.

Olympic events are often broadcast on a time delay. But this year, in the real-time complaint-box culture that social media has spawned, angry sports fans have taken to Twitter to denounce NBC’s coverage. The network streams events live online as they happen in London — five hours ahead of East Coast time — but holds the most popular events like swimming off the air until prime time in the United States.



This has resulted in more than a few spoilers for major events like Michael Phelps’s failure to win a medal in his first race at the London Games. Meanwhile, NBC has had no problem leading its evening newscasts with word of the day’s winners and losers in London, well before the prime time broadcasts begin.

But no spoiler was quite as embarrassing as the “Today” slip-up. The short commercial shown on Monday night promised viewers of Tuesday’s “Today” that they would be given the exclusive interview “live from London” — one of the few instances when “live” actually meant it in this Olympics.