(Adds Brazil's Silva)
By Nick Mulvenney
LONDON, July 31 (Reuters) - The International Olympic Committee (IOC) has no regrets about embracing social media for what some are calling the first "Twitter Games", despite two athletes having been expelled for tweets and others being abused online.
Swiss soccer player Michel Morganella was sent home from the Olympics on Monday for an offensive tweet aimed at South Korea, while triple jumper Paraskevi Papachristou was thrown out of the Greek team last week for a racist comment.
On Tuesday, British police arrested a man after offensive tweets were sent to British diver Tom Daley when he failed to win a medal in his first event.
Brazilian judoka Rafaela Silva also vented on Twitter, though coach Rosicleia Campos said the 20-year-old athlete's outburst had been sparked by racist taunts that were posted after she was disqualified for using an illegal move. Brazil soccer striker Neymar, who is at the Games, also came to her defence on Twitter.
Despite these incidents, IOC spokesman Mark Adams said the Olympic ruling would continue to encourage the use of social media around the Games and was probably powerless to stop it even if it wanted to.
"As you know the IOC, the Olympics we have about 15 million social media fans and I think (local organisers) are doing something similar," he told a news conference on Tuesday.
"To be frank, it'd be a little bit like King Kanute even if we said these aren't social media Games, because everyone's decided they are anyway.
"We want to help people have a good time in social media."
Twitter was in its infancy when the last Summer Games took place four years ago and was not a major factor in Beijing, where inappropriate blogging was the main concern.
The IOC, keen to attract a strong following among the world's youth for the Games, issued guidelines for the use of social media in London in June 2011.
They encouraged athletes to "post, blog and tweet their experiences" as long as it was not done for commercial or political purposes. Anyone breaching the rules faces having their accreditation removed.
A group of U.S. athletes chose Twitter to launch a campaign against Olympic restrictions on the promotion of personal sponsors at the Games on Monday.
Rule 40 of the Olympic Charter protects the major sponsors of the Games, both local an international, from "ambush marketing" by limiting what athletes, and others, can promote within the environs of the Olympics.
Adams said, however, that the existence of Twitter had not altered the rules, just the application of them.
"I don't think we have any major concerns, as you know those rules, such as Rule 40, have been around for a long time before social media. Social media's only been round for six or seven years," he said.
"Clearly issues are raised more quickly but they're still the same issues that we have to deal with, and if an athlete makes a comment which contravenes those rules as has happened, we will take action.
"Used in the right way, we embrace social media."
Adams would not comment on the suspension of the Twitter account of a journalist for tweeting the e-mail address of a senior NBC executive after criticism of the coverage of the Olympic opening ceremony in the United States.
"That's between NBC and Twitter," he said. (Additional reporting by Pedro Fonseca; editing by Ed Osmond and Jason Neely)