United States its been consider Facebook’s most developed market with 168 milion users folllowed  by Britain.

Like most websites Facebook normally experiences a slowdown in traffic over the festive period as people unplug from the internet. Among Facebook’s top 10 biggest markets, Britain was the only one where the number of visitors actually fell.

Social networking observers have long expected the service to reach saturation point at around 50 per cent, and have seized on SocialBakers’ December data as supporting evidence. Facebook’s growth curve has been slowing for several years.

Jan Rezab, SocialBakers chief executive, agreed Facebook was probably at saturation point in Britain but warned against seeing the December data as evidence it had begun to go backwards. He concluded that 15 per cent of the population are under 13 years old and not allowed on Facebook and 16.5 per cent are in the over-65 age bracket, which accounts for only 4 per cent of the 33 million British members.

“This effectively means that UK is inflecting in terms of numbers at near full penetration on Facebook,” he said.

“I can’t imagine their fans could grow by 10–20M new users, although this depends if they allow teens under 13 on the platform and furthermore largely depends on their mobile adoption.”

Mr Rezab declared that was quite chalenging to compare years due to rapid growth of social networks in recent years and hard to assess the impact of the Christmas season on Facebook traffic.

“The monthly active user count is statistically vulnerable to more casual users of the platform, users that don’t use it that often and might fall out of the 30-day range from time to time… my grandpa might sometimes not be an active user on Facebook, even though he is using it,” Mr Rezab said.