Facebook and Nielsen are joining forces as part of an ambitious campaign to better measure how consumers are using their mobile devices for accessing entertainment media. As part of the mobile ratings Nielsen plans to introduce this fall, Facebook will scan its databases for the age and gender of its users who watch a TV show on their phone or tablet. The data will be shared with Nielsen and ultimately help networks and advertisers learn more about the viewing habits of consumers.

Nielsen is expanding beyond the traditional family unit and TV set in recruiting the assistance of Facebook, Experian Marketing Services and other data aggregators.

“The very definition of ‘watching TV’ has been changing fast,” reports the Los Angeles Times. “People are going from watching ‘channels’ on TV sets in their living rooms to taking in their favorite shows on laptops, smartphones, tablets and, soon, their wristwatches. They’re mobile, tuning in from the car, a train, the beach, the classroom or even the grocery store.”

“The world is shifting radically, and so we had to evolve our measurement so that we could capture all of this fragmented viewing,” said Cheryl Idell, a Nielsen executive vice president.

However, not surprisingly, privacy advocates are concerned that consumers will unknowingly be sharing their information.

“It’s interesting to me that I’m watching a video somewhere and somehow Facebook knows that,” said Chris Conley, an attorney at the American Civil Liberties Union.

“Consumers really are not aware of the extent to which Facebook is putting their non-Facebook activity to use,” said Julia Horwitz, counsel at the Electronic Privacy Information Center. “Watching television and surfing the Internet shouldn’t necessarily involve Facebook.”

Meanwhile, Facebook and Nielsen explain that the process is anonymous and shields people’s identities.

“There’s a lot at stake,” notes the article. “Television advertising is a $65-billion-a-year business. Separately, online video advertising is one of the fastest-growing segments, according to research firm eMarketer. Digital video ad revenue is expected to expand 40 percent this year to $6 billion.”