New figures have revealed that although Facebook is still the dominant social media site, it has started to experience a slight drop in usage.

The figures, from Experian Hitwise, show that in December Facebook’s share of all UK visits to social media network sites, amounted to 52.6%.

Although impressive, and well above its rivals, the figure compares unfavourably with that for December 2010, when Facebook’s usage share stood at 58.5%.

The concern expressed at this drop by some commentators has been further heightened by the revelation that the social media site lost 1.3% of its usage share in December alone.

Commenting on the findings, however, Experian market research analyst, James Murray, said they showed merely that ‘Facebook’s growth is levelling out’:

‘Because Facebook had such a clear lead’, he said, ‘it was always going to be difficult for Facebook to maintain [its position]’.

Murray added that, in his view, Facebook ‘has probably reached near enough its maximum growth’.

In spite of this, the findings will be seen by many commentators as not quite being what Facebook had expected; especially given the social media company’s recent substantial investment in trying to attract more members to the site; and its reported intention to float on the stock market this year.

Percentage usage share data for other social media sites in December stood at: just over 25% for YouTube; 3% for twitter; and 2% for Yahoo! Answers.

All the latter social media sites’ percentages represented a growth over those registered the previous year.