Google came out top across all websites in terms of total unique visitors, with its 173 million beating second placed Facebook by over 20 million. Yahoo completed the top three, while Wikipedia came in 8th place with 76.3 million.  The top ten...also included the likes of Youtube (127.5 million) and Amazon.com (76.1 million)...

Each month Nielsen also focus on websites from a specific sector, and this time they analysed online news providers. The Yahoo!-ABC News Websites group had the most unique visitors - over 62 million - during May, with the CNN Digital Network (39.6 million) some way behind in second.

HPMG News Websites (formerly AOL News) rounded off the top three, with MSNBC and the New York Times in fourth and fifth. Also featuring among the top ten were the Huffington Post and Fox Digital News Network.  Of the ten most visited sites, CNN came top in terms of the average number of minutes per month spent browsing. Along with Fox, these were the only two sites on this list to surpass 30 minutes per user per month.