Facebook is becoming a key source of news for users of the huge social network, even if people discover articles mostly by happenstance, a study showed Thursday. The study by the Pew Research Center, in collaboration with the Knight Foundation, found 64 percent of US adults use Facebook, and nearly half of those get some news from the service. That amounts to 30 percent of the overall US population who are \"Facebook news consumers,\" Pew said. But the survey found 78 percent of this group get news mainly when they are on Facebook for other reasons, such as checking on friends or sharing photos. \"People go to Facebook to share personal moments -- and they discover the news almost incidentally,\" said Amy Mitchell, Pew Research Center\'s director of journalism research. \"The serendipitous nature of news on Facebook may actually increase its importance as a source of news and information, especially among those who do not follow the news closely.\" Most heavy news consumers do not describe Facebook as their main source of information on current affairs: Some 38 percent of Facebook news consumers who say they follow the news \"all\" or \"most of the time\" describe the social network as an important way they get news. But that number rises to 47 percent among those who say they follow news just \"some of the time\" or less. Those in the 18- to 29- year-old age bracket account for about a third of Facebook news consumers. These younger adults often turn to the social network for breaking news and see the site as important a source of news. The study authors write that Facebook \"exposes some people to news who otherwise might not get it\" by delivering news through shared links from friends. \"This study adds to our understanding of the way social media is transforming how news is shared and consumed,\" said Mayur Patel, Knight Foundation vice president. \"The implications for media organizations are significant -- through the data they can gain insights on the behavior and preferences of the people they are trying to reach, and identify new engagement opportunities.\" Roughly two-thirds of Facebook news consumers say they at least sometimes click on news links, and 60 percent at least sometimes \"like\" or comment on stories, the researchers found. About four in 10 post or share links themselves at least sometimes, and 32 percent discuss issues in the news with other people on Facebook, the survey found. The study found Facebook users click on a news link most often because of their interest in the topic or a friend\'s recommendation, and just 20 percent said they did so because of the news organization. About a third of Facebook news consumers have news organizations or individual journalists in their feeds, Pew found. The researchers also found that Facebook users are also consuming news on other platforms. Some 42 percent of Facebook news consumers often watch local television news, compared with 46 percent of all US adults. But just 21 percent often read print newspapers, compared with 27 percent of the population overall, Pew found. The researchers interviewed 5,173 US adults including 3,268 Facebook users from August 21 to September 2, 2013.