The home page of social networking site Facebook is now a more popular destination for US web surfers than Google, according to Hitwise, which tracks Internet usage.The US research firm, owned by the UK's Experian Group, said that that 7.07% of all Internet requests in the US during the week ending 13 March involved a visit to Facebook, compared to a 7.04% share for search engine titan Google. It is first time that the number of visits to Facebook over a week have exceeded hits on Google's US search page.The social networking site's US user base is growing faster than that of Google, so the trend looks likely to continue. In April of last year Facebook had 200m users, according to Hitwise, but this number had grown to 400m in February 2010. The number of hits on Facebook in the week to 13 March was 185% higher than a year earlier, whereas Google's hits only increased by 9% year on year.However, when comparing the relative popularity of the two sites it would be wise to remember Benjamin Disraeli's old adage about 'lies, damn lies and statistics', because the Hitwise figures for Google only count visits to Google.com.As might be expected for a survey of US browsing habits, the figures exclude visits to localised versions of the ubiquitous search engine, such as Google.co.uk, but they also exclude searches conducted through browser search panels. Browsers such as Opera, Firefox and, of course, Google's own Chrome browser, routinely have Google as the default search engine in their search panels; Microsoft's Internet Explorer defaults to Bing, the Microsoft rival to Google.The figures also exclude Google queries made from sites that offer the Google search engine as a tool on their web pages. As the clear market leader in search Google technology is frequently chosen by web sites that integrate web search into their pages. In the UK, newspapers such as the Daily Telegraph and The Independent offer a Google search panel, while even The Times, whose proprietor Rupert Murdoch is a vociferous critic of Google, uses Google technology to process search requests.Nevertheless, the seemingly unstoppable rise of Facebook will concern Google, if only because the social networking site's content is closed to it's indexing robots. If Google cannot index Facebook content, it cannot make any advertising revenue from it. Its response has been to take a leaf out of Microsoft's play-book, and try to leverage its dominant position in search and, to a lesser extent, e-mail, to launch a rival social networking service.The service, called Buzz, got off to a less than auspicious start in February when its decision to track each Buzz account holder's Gmail (known as Google Mail in the UK) traffic and automatically add frequent mail recipients to the user's 'followers' in their Buzz account raised concerns about privacy.As an example of how this automated feature might backfire, imagine you are a Premiership footballer who is frequently e-mailing the ex-partner of a team-mate. The Buzz auto-follow feature would automatically add the ex-partner to the footballer's followers on his Buzz page, possibly causing him some embarrassment should his team-mate visit the page. Google quickly moved to change its default settings on its Buzz account settings to make this feature a proactive 'opt-in' feature.