Some Olympians stumble on Twitter

(CBS News) Some frustrated Olympians are learning the hard way to be careful what they tweet. Two athletes have been sent home for messages that are considered racist.

Swiss soccer player Michel Morganella was booted from the London games for this nasty tweet calling Koreans a "bunch of mongoloids." The Twitter tirade came after the South Koreans defeated Morganella's team. Now his Olympic dream - like his Twitter account - is "no longer available."

Greek athlete Voula Papachristou was also cast out of the games for a biting tweet she sent just days before the opening ceremony: "With so many Africans in Greece, the West Nile mosquitoes will be getting home food!!!"

Twitter, like the Olympic Games, is supposed to bring a diverse world closer together. But these games - the first since Twitter took off in popularity - have instead been marred by thoughtless messages.

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Americans have had their own Twitter troubles, too. Superstar goalie Hope Solo refused to apologize for tweets she directed at soccer legend Brandi Chastain. Solo was upset by Chastain's commentary on a recent TV broadcast, writing, "Lay off commentating about defending and gking until you get more educated @brandichastain the game has changed from a decade ago. #fb"

Fans give athletes with faulty filters little empathy. Nahil Dhanji told CBS News, "They're supposed to be a sportsmen, and they're supposed to be the best of the best and being accountable for what you say is part of being a role model for the world."

Social media guru Jeff Jarvis says the Olympics must come to terms with this new 140-character reality.

Jarvis, author of "Public Parts," said, "The truth about Twitter and Facebook and blogs and the web is that you can't control speech or information any more and that's what the (International Olympic Committee) or governments and networks and businesses have to learn."

And it's not just the Olympians who have to watch their social media use. Fans have unleashed a torrent of texts and tweets and typing thumbs that at times has clogged London's mobile connections, interfering with the games themselves. So organizers have urged spectators to also take it down a notch.

There are more than 10,000 athletes in London for the games, and the IOC says it wants them to communicate with fans via social media. They've issued guidelines to make sure the discourse stays respectful. But, some countries like Greece, perhaps wanting to avoid any more controversy, have banned their athletes from logging on to share anything personal.