Facebook has overtaken MSN to become the UK’s second most popular website, fuelled by the over-50 age group.

A record 26.8m people in the UK visited Facebook in May, according to UKOM/Nielsen. The number of people visiting MSN stood at 26.4m.

Google remained the most visited website, with a 33.7m visitors in May.

Twitter and LinkedIn also recorded unprecedented visitor numbers, with Twitter reaching 6.14m and LinkedIn attracting 3.59m visitors, up 57% on May 2010.

Nielsen attributed Twitter’s record figures, up 34% on April, to the furore surrounding it and Ryan Giggs’ super-injunction.  A 65% increase in 50-64-year-old men and a 96% jump in women over-65 visiting the site helped boost numbers.

According to UKOM/Nielsen, older people are more likely to visit Twitter than younger age groups.

Nielsen has also pointed out that Facebook’s growth, despite reports earlier this month that its numbers had started to fall, was being driven by the over-50s. Since 2009, the number of 50-64-year-olds visiting the site has grown 84%.

These older users account for more new adults visiting the site in the last two years than the under-50s, said UKOM general manager James Smythe. As a result, the membership of Facebook is now more representative of the overall UK population. Twitter, however, looks to become increasingly skewed towards an older age group, with under-18s less likely to visit it than they were two years ago.

Earlier this month, Facebook rebuffed reports it was losing traffic in major markets. Social media blog Inside Facebook claimed its Gold Data service, analysing active Facebook users, showed that in mature markets including Canada, Norway, Russia, the UK and US, traffic had dropped (nma.co.uk 13 June 2011).

Facebook said the data, extracted from an advertising tool, wasn’t an accurate picture of its traffic.