LONDON — It’s amazing how much trouble can be stirred up in 140 characters or less.

But also how much intimacy, excitement, global scope and, yes, general zaniness. For better and for worse, the 2012 Olympics are being shaped, shaken and indisputably changed by a social media revolution that four years ago in Beijing was in its toddlerhood.

Four days into the games, we’ve already seen (and this is but a partial list):

* an athletes’ Twitter campaign objecting to sponsorship restrictions that went viral under the hashtag “WeDemandChange.”

* a television viewers uprising over Olympic broadcaster NBC’s decision not to live stream the opening ceremony.

* two athletes kicked out for racist tweets.

* a fan arrested Tuesday after a series of threatening posts, including one in which he vowed to drown a British diver, and another in which he told the athlete he had failed his dead father by not winning.

For Olympics organizers who pride themselves on putting on a carefully choreographed — obsessively controlled, some would say — 17-day show, the bursts of Twitter activity are like gamma rays escaping from a solar flare. They’re impossible to stop and spellbinding to behold.

“I don’t think we would seek to control it, nor could we,” said International Olympic Committee spokesman Mark Adams. He said more than 15 million fans are following and participating in the Olympic experience via Twitter and other social media platforms, not to mention a good proportion of the 10,800 athletes. “Used the right way, we embrace social media,” he said. “And, if you look at the guidelines, we positively encourage it.”

The problem is, it isn’t always used that way.

The immediacy and public nature of Twitter and its propensity to induce off-the-cuff irreverence, and sometimes breathtaking ugliness, has added a new and chaotic element to an event where everything from urine samples to sponsors’ logos to London traffic is arranged with overcaffeinated attention to detail worthy of a royal wedding.

“Though organizers have spent months touting this as the first social media Summer Games, many of them seem to have been totally unprepared for the huge impact that Twitter has had,” said Andy Miah, director of the Creative Futures Institute at the University of the West of Scotland. “I think there was some naivete about the likely role of social media from both participants and from the organizers. Many of them appear to have been wrongfooted.”