Google remained the most visited website, with 33.7million visitors. The number of people visiting MSN in May stood at 26.4 million.

Twitter and LinkedIn also recorded unprecedented visitor numbers, with Twitter reaching 6.14 million and LinkedIn attracting 3.59 million 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 to 64 year-old men, and a 96% jump in women over-65 visiting the site helped boost numbers.

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

Nielsen has also pointed out that Facebook 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 to 64 year-olds visiting the site has grown 84%.

These older age groups 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 than it previously has been. 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 that its Gold Data service, analysing active Facebook users, showed that in ’mature’ markets including Canada, Norway, Russia, the UK and US, traffic had dropped, and begun to slow overall traffic growth ( 13 June 2011).

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

This story first appeared on New Media Age. For more digital stories and analysis from NMA click here now