Discovery engine Stumble Upon leapfrogged MySpace to claim tenth place based on web traffic data from November, pushing MySpace down to eleventh.
All the other top ten sites in the category maintained their positions from October but YouTube increased its market share of visits by 0.67%.
Twitter, Gumtree and LinkedIn lost market share compared to October, while Facebook continued to grow, now accounting for 53% of all visits to social networks.
Experian Hitwise market research analyst James Murray said: "MySpace traffic has been on the decline for at least three years now but this is the first time the social network has fallen out of the top ten."
He added: "As the social media landscape continues to evolve, brands need to be aware of the fast moving trends and which social sites people are visiting."
In the search catergory, Google sites continued to dominate the market in November with a 0.05% increase in UK internet searches.
Google now accounts for 91.07% of all UK searches, with Microsoft sites in second place with 3.84% of searches and Yahoo! sites in third with 2.81% of the market.
Murray said: "Google is not only the biggest search engine in the UK but it is also the fastest growing search engine of November."
|Most popular Social Networks|
|Most popular social networks||Share of visits %
||Monthly||Share of visits %
|by UK Internet visits||Nov-11||change %
|Most popular search engines||Share of searches %
||Monthly||Share of searches %
|by share of UK searches||Nov-11||change %