Twitter is overseas Olympians' first choice of social media.

The London Games were once billed by the British Olympic Association's chief executive Andy Hunt as the "Twitter Games".

Six million users were on the service in 2008, compared to more than 600 million today - and London 2012 is expected to see an unprecedented amount of social media activity for a sporting event.

Tennis players have been some of the most active users. They have already been posting pictures and quips from Wimbledon and the Olympic Village.

Although strict guidelines from the International Olympic Committee are in place - as is advice from their own national Olympic committees - players are encouraged to share the Games' experience with the world.

Ten of the 16 men's singles seeds and nine of the 16 women's singles seeds are on Twitter.

Novak Djokovic of Serbia is the most followed male tennis player at the Games, with around 1.1 million followers, and local star Andy Murray is second, after recently breaking the 1 million mark.

Rafael Nadal of Spain, who was forced to withdraw from the Games because of injury, is the most followed men's player, with more than 2.7 million followers. World No 1 Roger Federer does not have a Twitter account, although he has more than 11 million "likes" on his official Facebook page.

Serena William of the US is the most followed female player with 2.9 million followers. Her sister, Venus, is second with around 845,000, and Sania Mirza of India - who ranks 247th in the world - is third, with around 626,000.

However, tennis players still fall way behind basketball superstar LeBron James - the most followed athlete on Twitter at the Games, with more than 5.5 million followers.

Sharpshooter Kevin Durant boasts 2.65 million, and All-Star guard Chris Paul has 1.37 million.

Among Britain's athletes who are most followed on Twitter is diver Tom Daley, with 500,000 followers.

But none of them are any match for China's tennis No 1 Li Na, who does not have a Twitter account but does have more than 6 million followers on her Chinese Sina Weibo.

There are more than 2,000 verified Olympians, present and former, on Twitter for London 2012.

chenxiangfeng@chinadaily.com.cn