Twitter shares tumbled Friday after a brokerage analyst warned the popular messaging network was overvalued following a meteoric rise since its initial public offering in November.

Twitter shares closed down 12.99 percent at $63.79. But the stock has more than doubled from its offering price at $26 on November 7.

Jon Ogg at 24/7 Wall Street said Friday's decline followed a five percent gain on Thursday which put Twitter at a record high of $73.31.

"Twitter's stock valuation has been difficult or impossible for Wall Street analysts to deal with," Ogg said in a blog post.

Ogg said at the start of the day, Twitter was trading at roughly 62 times expected 2013 revenues and about 35 times expected 2014 revenues.

"Another negative is that the company is expected to lose money in 2013 and in 2014," he added.

Twitter has become massively popular around the world, but some analysts are skeptical about its ability to boost usage and revenues to become profitable.

The catalyst for the selloff came from Ben Schachter at Macquarie who changed his rating to "underperform" from "neutral," noting that Twitter was up 40 percent since December 11.

"We continue to believe that Twitter as a company has a bright future and many opportunities ahead. However, as a stock, we believe nothing has changed over the last 15 days to justify the rise in valuation," Schachter said.

Meanwhile Bespoke investment group released a chart on Twitter noting that the stock appears to have paralleled Google market action in its early trading days.

Following up on that tweet, the investment firm tweeted, "Didn't say $TWTR was $GOOG, just highlighting how closely their caps have tracked in their early days after IPO."

Study: Teens abandoning Facebook, leaving it 'dead and buried'
London (UPI) Dec 27, 2013 - Teenagers are abandoning Facebook in large numbers, citing their parents as the biggest deterrent to their using the service, a European study found.

"Facebook is not just on the slide -- it is basically dead and buried," researcher Daniel Miller, professor of material culture at University College London, said.

A study of teens 16 to 18 years old in eight EU countries found as parents and older users saturate Facebook, its younger users are shifting to alternative platforms, the Guardian reported Friday.

The key age group of older teenagers is moving from Facebook to other services such as Twitter, Instagram, WhatsApp and Snapchat, researchers conducting the Global Social Media Impact Study said.

"Mostly they feel embarrassed to even be associated with it," Miller said. "Where once parents worried about their children joining Facebook, the children now say it is their family that insists they stay there to post about their lives.

"What appears to be the most seminal moment in a young person's decision to leave Facebook was surely that dreaded day your mum sends you a friend request," Miller said.

"It is nothing new that young people care about style and status in relation to their peers, and Facebook is simply not cool anymore," he said.