In 2011, Twitter leaped into action

This is the year a 5 1/2-year-old changed the world.

The name of this mighty mite? Twitter.

From the Arab Spring to the Japan earthquake and tsunami, from the death of Osama bin Laden to the Occupy movement, Twitter played a big role, with millions learning, reacting, connecting, and sharing instantly - far faster than old slowpoke media like radio and TV.

"Twitter? Oh, it's definitely mainstream now," says Kate Bussmann, author of A Twitter Year: 365 Days in 140 Characters.

"I see 2011 as the year of democratization for Twitter," says William L. Weaver, an associate professor of integrated science, business, and technology at La Salle University. "It's in the hands of Everyman, and Everyman is using it."

Born July 2006, Twitter now stands at 100 million users strong, and they tweet 230 million times a day.

"This is a dramatic coming-out of Twitter as a bullhorn for public events, a means of social organization," says Lee Rainie, director of Pew Research Center's Internet & American Life Project. "For many people, it's now the default, the reflexive move."

Proof people care

The year's hottest Twitter topic - seen in hashtags, that little pound sign (#) in front of a word or phrase that lets people find tweets containing it - was #egypt. No. 2 was #tigerblood, courtesy of the No. 1 most-tweeted-about actor, Charlie Sheen. (Liz Taylor was the top tweeted-about actress.) The top five most-tweeted-about places: Cairo, Egypt, Japan, Libya, and Tokyo.

You can track what people care about through the rates of tweets per second (TPS) worldwide at any given time, and also through the "trending topics" - topics of especially rapid growth in tweets.

The world record for TPS - 8,868 - had been about the baby bump for Beyoncé and her pregnancy announcement Aug. 28 at the MTV Music Video Awards. But on Dec. 9, that was smashed to bits by a furious eruption in Japan during the showing of the anime film Castle in the Sky, with a mind-numbing 25,088 TPS.

Sports and entertainment, up among earthquakes and antiterrorist raids? That shows Twitter is the province of the young, but it also shows that millions of us are multimedia mavens.

As Bussmann points out, "Many of these tweets are people sharing what they just saw on TV, or on the Web - they're using two screens, and two media, at once."