Bing officially went live on 3 June, although some country versions were available ahead of that date. Much of the gain was at the expense of Google, which is still the clear leader, and StatCounter said that it is too early to say whether Microsoft can sustain its position.
"It remains to be seen if Bing falls away after the initial novelty and promotion, but at first sight it looks like Microsoft is on to a winner," said Aodhan Cullen, chief executive at StatCounter.
Microsoft chief executive Steve Ballmer said recently that he wanted Microsoft to become the second biggest search engine within five years.
"Following the breakdown in talks to acquire Yahoo at a cost of $40bn [£25bn], it looks as if he may have achieved that with Bing much sooner and a lot cheaper than anticipated," said Cullen.
Bing holds roughly 16 per cent of the US search market, according to StatCounter's figures, while Yahoo has just over 10 per cent and Google 71 per cent. Worldwide, the numbers break down as six per cent, five per cent and 88 per cent respectively.
StatCounter also pointed out that Bing is not currently available in its fullest version in many locations, including the UK.
Visitors to the UK search page are given the sorts of options you might expect from a standard search engine, including tabs for news, images, shopping and the ability to see results from a chosen location.
However, selecting the US version of Bing brings up many of the additional options touted by Microsoft as key selling points of its new 'decision engine'. These include popular searches, a travel section, location-aware features such as 'restaurants in your area', and information relating to the pictures used to illustrate the Bing home page.
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