LONDON (Reuters) - Athletes racing to share their views with fans at the London Olympics may think twice before hitting send following the first expulsion of an athlete for a racist Twitter remark.
Greek triple jumper Paraskevi Papachristou was withdrawn from the London Olympics on Wednesday after causing an uproar in her home nation for a tweet about West Nile mosquitoes and the number of Africans in Greece.
Her expulsion was expected to act as a warning to other athletes who, along with Olympic organisers, are trying to find the best way to harness the power of social media that has exploded since the 2008 Beijing Games.
"The fact that this has happened will make other athletes feel more cautious about what they put out there," said Rebecca Hopkins, managing director of sports PR agency ENS Ltd that handles crisis media management.
"It is always very difficult to impose a limit on freedom of speech but the IOC (International Olympic Committee) has set down the guidelines and the athletes have to comply."
The explosion of social media in the past four years has created a new challenge for the IOC and for the National Olympic Committees who could previously resolve any indiscretions away from the public eye.
Since the Beijing Olympics, the number of Facebook users has surged to 900 million from 100 million and Twitter has 140 million users having only just emerged in 2008.
Aware that athletes and their fans are prolific users of social media, the IOC said competitors at the London Games may post, blog and tweet -- but within guidelines.
Competitors may write "first-person, diary-type" entries but should not act as reporters, and social media activity must respect the Olympic Charter which condemns any discrimination. Vulgar or obscene words or images were also ruled out.
Postings deemed to be for commercial or advertising purposes were also on the no-go list.
The IOC made it clear that the accreditations of "any organisation or person ... may be withdrawn without notice" if its guidelines are breached and most athletes were aware of the rules.
"The thing is you have to be careful with the social media side of things -- certainly the decision to tweet or not tweet, and certainly what you say," said British badminton player, Imogen Bankier.
The sports world has seen a fair number of social media abuses in recent years particularly among soccer players.
The English Football Association and New Zealand rugby board responded by banning their players from using social media during recent football and rugby union World Cups.
So far only a handful of Olympians have landed in hot water.
Australian swimmer Stephanie Rice lost a lucrative endorsement deal with Jaguar two years ago after tweeting a comment seen as homophobic.
Australian swimmers Nick D'Arcy and Kenrick Monk have been banned from using social media in London by the Australian Olympic Committee after posting a photo of themselves brandishing guns on Facebook while training in the United States.
They have also been ordered to return home immediately after the completion of their events at London.
Athletes said Wednesday's expulsion would be a wake-up call but would not stop athletes from using social media at the Olympics.
"Most of us I think are pretty good about it, and I've seen a lot of people in the sports community use it pretty wisely," said Chas Betts, a U.S. Greco-Roman wrestler.
"I think it can be very beneficial, you know, updates and things ... so for the most part I think it's a good thing."
Writing by Belinda Goldsmith; Editing by Frank Pingue