Reports of the death of Facebook have been "greatly exaggerated", the boss of a major market researcher into digital customers has said.
A recent article by a University College of London professor made headlines when he said many teenagers thought Facebook was uncool, as their parents and older people began to use it more. Professor Daniel Miller said the social networking giant was "dead and buried" to them.
But a bigger international study by London and Singapore-based GlobalWebIndex found that Facebook's decline among young people has been overstated, and it remains hugely popular around the world.
Tom Smith, founder and chief executive of GlobalWebIndex, said: "Academics from University College London recently received a lot of coverage by claiming that Facebook is 'basically dead and buried' among teens, but the real picture is actually far more complex.
"While teen usage of Facebook has seen a small decline, there is strikingly little evidence to suggest that UCL's findings are representative of broader trends."
Mr Smith said his firm's research was based on 170,000 online interviews per year across 32 countries.
"We've been able to show that Facebook is still used by 48.5% of 16 to 19-year-olds globally on a monthly basis," he said.
"Facebook is still the dominant, most popular social network on the planet among teens with 67% more active teen users than the nearest competitor, YouTube (29% of 16 to 19-year-olds). Twitter is third with 26% of 16 to 19-year-olds around the world using it on a monthly basis.
"Our GlobalWebIndex Social study shows that reports of 'the death of Facebook' have been greatly exaggerated."
Use of networking and messaging apps like WeCat, Vine, SnapChat and WhatsApp rose strongly too.
Though more than 50% of active users on the top social platforms are drawn from the 16-34 age group, it is the 25-34s rather than the 16-24s who form the largest share of users on nearly all of them.
Emerging internet markets are the most socially engaged. Indonesia tops the list with 97% of internet users having an account on Facebook, and 83% with a Google+ account.
Prof Miller's findings about Facebook came from nine months of ethnographic research at schools just outside London, he said.
"It was a very clear trend, and the schools themselves only use Twitter for communication with pupils, not Facebook, so they are well aware of these dynamics," he said.
"Mine is the clearest statement about Facebook having become completely uncool for teenagers, but statistics in the US are showing a clear trend in this direction and my current visit to Trinidad is suggesting the same.
"I have no evidence that this is true in other countries such as India or Brazil. The researcher in our site in southern Italy, for example, sees no evidence for a decline in Facebook usage in the classroom.
"Our project is based on nine sites in eight countries, some of which, as in China, have never used Facebook and we anticipate continued variation.
"It is not very surprising that young people want something new and cool after a few years and that is one of the main reasons they leave Facebook.
"It is also because they want to have a place where they can communicate with each other that is not the same as the site where they interact with their parents.
"These teens, at least in England, don't close their Facebook accounts, they keep it for family connections and photo albums, but the main usage is moving to older people.
"It is possible these young people will return to Facebook when they go to university, but I doubt it.
"There is no evidence that Facebook is losing its popularity with adults."
The academic stressed he never claimed that Facebook "itself was dead and buried".
He said: "I was only talking about the loss of cool amongst the young."