Online market tracker comScore has not officially released its August search engine rankings to the public yet, but second-hand reports from Wall Street indicate Microsoft's Bing made another steady jump, up from 8.9 in July to 9.3 percent in August.It's still a long way from Google \u2014 which reportedly dropped 0.1 percent in August to 64.6 percent \u2014 but Bing's growth has been consistent since the search engine launched in late May. Last week, metrics company Neilsen Co. listed Bing as growing more than comScore's latest numbers indicate. Nielsen reported that Bing's U.S. search share was up to 10.7 percent in August from 9 percent in July. Search engine rankings tend to vary based on which company is doing the measuring. For consistency, I use comScore's rankings, and will do so for this article.The comScore numbers reveal that Bing has grown a half a percentage point every month since May, while Yahoo has been dropping slightly each month (from 20.1 percent in May to 19.3 percent in August). Google has done the same, though to a lesser extent than Yahoo. Google fell from 65.0 percent in May and June to 64.7 in July and now to 64.6 percent in August, according to comScore.With Bing, Microsoft has been getting the kind of consistent share growth that it did not have before Bing launched. Live Search (its pre-Bing moniker) had been mostly flat month-over-month with slight dips in the first half of 2009, hitting a year low of 8.0 percent in Bing's launch month of May. If Bing keeps growing at its current rate it will reach 11 percent market share by the end of the year.Additionally, Microsoft continues to roll out updates for Bing. The most recent was last week's beta launch of Bing Visual Search, a new option where users can search for brands, people and places using Silverlight thumbnail images. Visual Search has received reviews both warm and cold. More updates for Bing, tentatively titled Bing 2.0, are rumored to take place later this fall with additional mapping and Silverlight features supposedly in the works, according to tweets from Microsoft employees who have seen a Bing 2.0 demo.It's doubtful Googleites are losing much sleep over such incremental gains, but Microsoft is moving aggressively with Bing, marketing it all over the Web and rolling out new features almost monthly, with steady market share gains to show for it. Making Bing more of a threat to Google is Microsoft's recent search agreement with Yahoo under which Bing will power Yahoo's sites while Yahoo sells search ads for both companies. If Google isn't tossing and turning yet, it certainly will if the Bing momentum keeps up. Are you a Tweeter? Follow me on Twitter at twitter.com\/smoneill. Follow everything from CIO.com on Twitter at twitter.com\/CIOonline.