Facebook is now the second most used website in Britain, behind instant messaging service Windows Live Messenger, previously known as MSN Messenger, which has fallen dramatically.
Time spent on WL Messenger, which allows users to chat online in real time, has dropped dramatically from 3.2bn minutes per month in April last year to 2.4bn this April.
Alex Burmaster, a Nielsen Online anaylst, said: “Facebook will over take WL Messenger very soon. There has been a seismic shift in a relatively short space of time. Social networks have fundamentally altered the way people communicate online.
“Consumers aren’t spending significantly more time online than they were a year ago, so if one sector grows, another tends to shrink.”
Facebook launched its own version of WL Messenger in April, a move which analysts believe will hit the instant messenger service harder still.
Auction site eBay is Briton’s third most popular website, holding steady at 1.7bn minutes a month.
Fourth was Google, up from 700m to 900m, and YouTube was fifth, up 200m to 600m. Facebook has more than eight million members in the UK.