After months of slow but steady increases in its market share, Bing‘s share of the search market in the US and globally fell for the first time in September. According to StatCounter’s Global Stats, Bing’s share of the search market in the US fell from 9.64% in August to 8.51% last month. Globally, Bing didn’t fare much better, as it went from 3.58% to 3.25%. Yahoo’s share went from 10.5% in August to only 9.4% in September. The combined share of Bing and Yahoo has now fallen to 17.91%.

According to StatCounter’s CEO Aodhan Cullen, this downward trend for Bing began in the middle of August. The launch of Bing’s visual search feature should have given Bing a nice boost in publicity last month, but if we can trust StatCounter’s data, this wasn’t enough to counter the downward trend that already began in August.
Source: StatCounter Global Stats – Search Engine Market Share
In the long run, these numbers could obviously turn out to be nothing more than a blip on the radar for Bing. After all, even the numbers for Google fluctuate every month. We also haven’t seen numbers for September from other analytics firms like Hitwise or Compete yet, though while they often differ, they usually agree with StatCounter when it comes to general trends.
The question, of course, is why Bing stopped growing last month. Did Microsoft scale back its marketing campaign? Or did users, after the novelty wore off, simply go back to Google?