So popular has the platform become since its launch in 2006 that even FIFA president Sepp Blatter has opened an account to "connect with football fans" during the tournament -- twitter.com/seppblatter.
"It is the first FIFA World Cup in which social media websites will play an important role in connecting everyone who cares about the game of football," he said.
"I'm very excited to be sharing my own personal experience of the 2010 FIFA World Cup with football fans from all over the world."
FIFA is also providing World Cup match updates via Twitter, and many players have been getting in on the act.
But traffic spikes have overwhelmed capacity, exposing internal flaws, as record numbers of people tweet.
Twitter saw the potential of one of the biggest sporting events in the world and set up its own site -- twitter.com/worldcup/worldcup -- featuring a continuous stream of "Top Tweets", messages from players, teams and others.
Users can also isolate messages from regular Twitter users by individual match or team and it published a list of suggested accounts to follow during the tournament.
But it was not available at times on Wednesday, with a picture of a whale -- known as the "fail whale", appearing instead with the message 'Twitter is over capacity'.
The outages have been coming thick and fast, spoiling the experience for fans.
"We're working through tweaks to our system in order to provide greater stability at a time when we?re facing record traffic," said Twitter spokesman Sean Garrett.
"We have long-term solutions that we are working towards, but in the meantime, we are making real-time adjustments so that we can grow our capacity and avoid outages during the World Cup."
When they can, players have been tweeting on the tournament, including Brazil's Kaka and Luis Fabiano, France's Nicolas Anelka, Uruguay's Diego Forlan and about half of the USA team.
Kaka tweeted 'I love you" to his wife Caroline while Italy's Guiseppe Rossi said 'Enjoying it over here. Seatbelt fastened and ready to go'.
Even players who are not in South Africa are joining in, including regular tweeters, Brazilian greats Ronaldo and Ronaldinho.
Some national coaches though don't like the distraction and have banned their players from all social networking sites -- Twitter and Facebook included.
"Hello everyone, from today we cannot connect until we get back from the World Cup, I will tell you about it when we get back! Greetings!" said Barcelona and Spain defender Carles Puyol.
England coach Fabio Capello has issued similar orders while the Dutch squad have been barred after striker Eljero Elia made a racist slur against one of his own friends.
During an Internet chat and an online game, the SV Hamburg winger described one of his friends as a "Moroccan cancer", prompting the response that he was a "nigger".
The exchange, filmed by the player's webcam and posted on the Internet, created a stir in the Netherlands.
"We have under-estimated the impact of the new forms of communication. We wanted to give the players freedom, hoping they would act in a responsible manner," said team spokesman Kees Jansma.
"It's a real pity, but we will no longer allow them to communicate using new media."