This Olympics, you don’t need a beam routine, a two-hour marathon time, or even a ticket to London to be a part of the games. With an anticipated audience of 4.9 billion worldwide, the Olympics will be seen in person, on television, and, more prominently than ever before, online.

In the four years since Beijing, the social media world has changed. In 2008, the Facebook IPO was nothing more than a glimmer in Mark Zuckerberg’s eye, Twitter saw just 100 million tweets per quarter (it’s 340 million a day now), and Foursquare, Google+ and Pinterest didn’t exist. All these changes mean that for users around the globe, the walls of Olympic Village have come down.

Social media is particularly important to the games’ sponsors. Official sponsors pay big bucks to emblazon the iconic Olympic rings on their brands—the exact value of sponsorship is a closely guarded secret, but CNBC reported that top-level sponsorship is thought to be in the $100 million range—and they are leveraging that value online. The trick for marketers is to focus on the athletes and the individual social media user, not on their brands.

Consumer goods giant Procter & Gamble is going for advertising gold. The company, known for products like Tide and Pantene, is hitting the social media circuit hard with its “Thank you, Mom” campaign. Global brand manager Marc Pritchard anticipates that social media activities will account for half the company’s ad impressions. Compare that to its sponsorship of the Vancouver Winter Olympics, where social media resulted in just 10 percent of impressions. Pritchard told USA Today, “We have evidence that our social media space provides a better return than TV."

With another 13 days of Olympic fever to go, P&G’s social media space is already seeing big numbers. The company’s centerpiece “Best Job” ad has already reached 14 million hits on YouTube, and the “Raising an Olympian” series featuring athletes and their mothers has been viewed 28 million times. The “Thank you, Mom” Facebook page boasts more than 700,000 likes. And the “Thank you, Mom” Twitter account has over 30,000 followers.

Coca-Cola is demonstrating its knowledge of the social media consumer with a campaign tailored to the individual. With an app that allows users to mix their own beats for their social networks, the company hopes to provide relevant, share-worthy content that will reach 1.5 billion people. Senior Vice President of Integrated Marketing Wendy Clark is confident the company's involvement in social media is a good marketing decision. “The numbers have passed the skeptics at this point,” she told USA Today. “We don’t spend this amount of time on things that don’t work.”

Visa, an official sponsor for 25 years, is going beyond sharing ads with social networks by inviting its fans and followers to help create its ads. Social media users are invited to “cheer” for athletes in Facebook and Twitter posts; the cheers of select fans will appear in a commercial. Official timekeeper Omega has become the unofficial Olympics historian. With a timeline of games’ trivia, the watchmaker, like many companies, is hoping to capitalize on what President Stephen Urquhart called “the chance of a lifetime to use social media.”