A week of Twitter mania culminated on Friday with actor Ashton Kutcher winning a popularity contest against cable news giant CNN on the Web platform and Oprah Winfrey sending her first tweet.

Even though Twitter mystifies many people, its celebrity appeal has generated interest. This week, What Happens in Vegas star Kutcher added to the buzz by challenging CNN to be the first Twitter user with 1 million followers.

Kutcher crossed that mark on Friday, beating CNN's breaking news Twitter feed by a beak, as the cable channel attracted its millionth follower 30 minutes later.

On Friday, Twitterati everywhere held their breath as the influential Winfrey sent her first message using the system. Feeling really 21st century, she wrote.

Twitter is an Internet-based tool that allows individuals or organizations to send short messages to computer screens and mobile devices, alerting followers about anything from breaking news to the sender's sometimes mundane activities.

It definitely has its detractors, said Karen North, director of the University of Southern California's Annenberg program on online communities.

The detractors are the people who think it's just ridiculous that people are saying things like, 'I just ate a taco,' North said.

CELEBRITY TWEETS

The San Francisco-based company behind Twitter was founded in 2006 but it has taken off in the United States in a huge way in recent months with everyone from politicians to Hollywood celebrities letting their fingers do the talking.

President Barack Obama used Twitter during his campaign last year, and prominent celebrities on Twitter include basketball star Shaquille O'Neal and singer Britney Spears.

As a private company, Twitter does not disclose its number of users. But Forrester Research senior analyst Jeremiah Owyang said Twitter has an estimated 5 million registered users and is the Web's fastest-growing social network.

The more established social networking site Facebook has more than 200 million users, he said.

A Twitter message can be no more than 140 characters, but it can link to another Web site. Kutcher's Twitter page on Friday had a link to charity organization Malaria No More.

Kutcher, 31, who is married to actress Demi Moore, vowed to buy 10,000 mosquito nets to fight malaria in developing countries if he beat CNN, and the cable channel has promised to give the same number of nets. Winfrey on Friday posted a Twitter message promising 20,000 nets.

On her talk show on Friday, Winfrey sat with Twitter CEO Evan Williams as she learned how Twitter works. Within eight hours of sending her first tweet, Winfrey already had more than 166,000 followers on Twitter.

The Kutcher vs. CNN race and Winfrey's first tweet were a milestone for Twitter, Owyang said. There's going to be a lot of new people trying it out today, he said.

While Twitter as a company is not yet turning a profit on the platform, users are capitalizing on it.

Whether you're an Oprah fan or not, the fact is Oprah can teach a lot of people about a number of important topics, and she now has a new medium with which to do that, North said.

(Reporting by Alex Dobuzinskis: Editing by Jill Serjeant)

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