by Jennifer Wilson, CBCNews.ca

Social networking site Facebook suffered its first drop in British users in January, web monitoring firm Nielsen Online research found.

Media reports say this is the first drop in UK users - falling 5 per cent from 8.9 million in December to 8.5 million in January - since Nielsen starting watching the network's numbers in 2006. The firm monitors 40,000 British computers to measure on- and off-line internet activity.

Facebook had reported 17 successive monthly increases in the country prior to January's drop.

Despite the UK losses, Facebook has still grown 712 per cent in the past year, and nine per cent in the past three months, the web monitoring firm said.

Some media reports suggest the dropping numbers comes from flagging popularity among young people as more adults, politicians and companies are logging on.

Alex Burmaster, a European internet analyst with Nielsen, told AFP that the decline in users doesn't signal a failing Facebook.

"Just as one swallow doesn't make a summer, so one month of falling audiences doesn't spell the decline of Facebook or social networking," he was quoted as saying. "It was inevitable that the early growth rates couldn't be sustained and the larger networks have been plateauing over the last few months."

The data also showed that users of second-place social networking site MySpace had dropped by 5 per cent, while third-place Bebo lost two per cent of its audience.

Burmaster was quoted by the BBC as saying less popular social networking sites, such as Windows Live Space, BBC Communities and Friends Reunited saw a rise in users in January.