NEW YORK — Social media companies have “friended” the 2012 presidential contest at a level almost unimaginable just four years ago, hosting debates and sponsoring presidential town halls while remaining indispensable tools for candidates looking to connect with voters in the digital sphere.

Social networking giants like Facebook and Google cast their involvement as civic engagement, saying they are eager to help facilitate the national political conversation and encourage people to vote. But their stepped-up political presence comes as those companies and others hire lobbyists, form political action committees and nurture their relationships with lawmakers whose policy decisions affect the companies’ bottom line.

“The exposure — being branded as ‘the’ place to go for social media — has huge economic consequences for these companies,” says Heather LaMarre, a journalism professor at the University of Minnesota who studies politics and the Internet. “When they appear to be socially active and engaged in democracy, they develop a vast well of good will with the political elites who have the ability to make or break them in the future.”

Facebook, by far the largest and most influential of the online social networks, formed a PAC this month to make contributions to candidates. The company also spent $550,000 for 21 lobbyists in the first half of this year to help it navigate potential legislative battles over privacy, patent and regulatory issues. That figure is small compared with other media companies of its size, but well on its way to double the $350,000 Facebook spent in all of 2010, according to the Center for Responsive Politics.

At the same time, Facebook has boosted its visibility in the presidential contest. The company is scheduled to co-host a Republican primary debate in New Hampshire with NBC’s “Meet the Press” days before that state’s first-in-the-nation primary. Facebook founder Mark Zuckerberg interviewed President Barack Obama in April.

The company is stocked with political veterans. Sheryl Sandberg, Facebook’s chief operating officer, worked for then-Treasury Secretary Larry Summers under President Bill Clinton. The company recently hired Joel Kaplan, a former domestic policy adviser to Republican President George W. Bush, to head its public policy office in Washington.

Showcasing both sides of the political divide has helped Facebook stress neutrality. “The color of the site is blue, but the color of the company is definitely purple,” Facebook spokesman Andrew Noyes said.