Though social networking site Facebook remains the most popular social networks by UK Internet visits, the share of visits of the site has dropped by nearly 4% in July when compared to June.

According to Internet search tracker Experian Hitwise, Facebook lost its market share of visits to reach 50.14%, its lowest since October 2009.

Experian Hitwise said that Facebook "suffered a significant loss of market share of visits this month dropping from 53.72% to 50.14% of all UK Internet visits to social networks.

"Facebook’s dominance of the UK social market hasn’t been this low since October 2009, when the network accounted for 50.46% of all visits to the category."

The Internet tracking company also said that YouTube became the fastest moving social network for the fifth consecutive month.

It said, "The search term ‘youtube’ was also the third biggest after term typed into search engines this month. The most popular search term was ‘facebook’, while ‘ebay’ was second."

"YouTube continued its exceptional growth as the fastest moving social network for the fifth consecutive month. One in every 35 visits to a website by UK Internet users now goes to YouTube and the video site now accounts for 22.54% of all visits to social networks, its highest market share of the UK social landscape recorded to date," said the firm.

The firm said that while Google sites maintained their robust lead at 91.04% of searches in July, it lost 0.98% share.

Microsoft Sites reclaimed the number two spot in the search engine rankings list having dropped to third last month for the first time this year. Microsoft Sites, led by the bing search engine, accounted for 3.84% of all UK Internet searches conducted in July 2011.

"Microsoft has recovered from last month’s blip to once again become the UK’s second most popular search provider," commented Experian Hitwise research director Robin Goad.

"The gains made by Microsoft Sites this month are almost exactly equal to the losses suffered by Google, which means that some of the searches that were being conducted on Google engines last month are now being typed into bing. "

Yahoo Sites increased their market share of visits slightly this month to account for 3% of all UK searches online, said the firm.