Facebook has reached the peak of its popularity and the social network could lose up to 80 per cent of its users by 2017, a study said.

Academics at Princeton University used theories on the spread of disease combined with Google Trends data on searches for Facebook to predict the demise of the world's largest social network, a Sky New report said.

They said the social network site has already entered a decline phase.

"The future suggests that Facebook will undergo a rapid decline in the coming years, losing 80 per cent of its peak user base between 2015 and 2017," the researchers said.

Facebook is worth $140 billion and has more than one billion users worldwide.
 Researchers looked at the number of Google searches for Facebook, and found that they peaked in December 2012.

A similar spike in searches was observed for Myspace months before it hit its peak in 2008, before heading into terminal decline.

The report said that every user who joins a social network expects to stay indefinitely, "but ultimately loses interest as their peers begin to lose interest".

They compared the decline of social networks to the spread of disease, adding: "Eventually, users begin to leave and recovery spreads infectiously as users begin to lose interest in the social network."

Prof Daniel Miller of University College London said simpler social networks such as Twitter and Snapchat would replace Facebook.

He added that part of the reason for young people leaving was their parents' decision to join.

"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," he said.

However some critics have pointed out flaws in the Princeton study, the Sky News report said.

It is based solely on Google search data, when more and more users now access Facebook using mobile apps rather than through a browser. It is not peer-reviewed either, meaning other academics have not had the opportunity to challenge and critique its findings before publication.