Social networking website Facebook has capped a year of phenomenal growth by overtaking Google’s popularity among US internet users, with industry data showing it has scored more visits on its home page than the search engine.

In a sign that the web is becoming more sociable than searchable, research firm Hitwise said that the two sites accounted for 14 per cent of all US internet visits last week. Facebook’s home page recorded 7.07 per cent of traffic and Google’s 7.03 per cent.

It is the first time that Facebook.com has enjoyed a weekly lead over Google.com. The lead may be slim, but it has become inevitable as Facebook’s popularity has grown rapidly from just over 2 per cent of visits a year ago. Heather Dougherty of Hitwise said that Facebook had “reached an important milestone” with the weekly figures.

Facebook’s membership has more than doubled in the past year, passing the 200m mark last April and 400m in February.

“The true value of Facebook and social networks is just becoming clear to marketers,” said Augie Ray, analyst at Forrester Research.

Although Facebook is enjoying rapid growth, it is only beginning to cash in on its success. Revenues at the social media company are estimated to be in the range of $1bn to $1.5bn this year, while Google took in $23.7bn last year.

Google has responded to the ascendancy of the social networking site with its own Buzz service last month. Buzz allows users to add status updates, friends, pictures, videos, location information, comments and links to other networking sites. Buzz, though, has struggled with privacy concerns just as Facebook has been criticised for encouraging members to reveal personal data to search engines.

The Hitwise figures only cover visits to the Google.com site, meaning that services such as Gmail, YouTube, Google Maps and searches carried out in a box in a browser toolbar are excluded. Taking all Google properties into account, the internet company accounted for 11.03 per cent of US website visits last week, compared with 10.98 per cent for Yahoo properties and 7.07 per cent for Facebook, according to Hitwise.

Facebook’s trajectory suggests that it will soar ahead of Google.com in the coming months. However, social networking sites have fallen in the past. Google.com had led since September 2007, when it overtook News Corp’s MySpace.com.

Internet users worldwide spent more than five-and-a-half hours a month on social networking sites such as Facebook and Twitter in December 2009, an 82 per cent increase over the previous year, according to the Nielsen Company research firm.

US users spent nearly six-and-a-half hours on Facebook compared with fewer than two-and-a-half hours on Google.