It was announced last year, but now it’s official: “Bing powers AOL’s web, mobile, and tablet search, providing paid search ads and algorithmic organic search results to AOL’s properties worldwide.” Citing comScore data, Microsoft now says that Bing is behind “close to one-third of US PC web searches.”

Beyond providing web search results for Siri on Apple devices, most of the Bing search volume is on the desktop. Last April, Bing crossed the 20-percent market share threshold on the PC. Today, it stands at just under 21 percent. Adding in Yahoo organic, and now AOL results, Bing is responsible for something like 34 percent of organic search results versus Google’s nearly two-thirds.

Last year, Bing and Yahoo, under the terms of a renegotiated deal, agreed that 51 percent of Yahoo algorithmic results must carry Bing Ads. That doesn’t extend into mobile, however.

In mobile search, Google is more dominant than on the PC, with more than 90 percent market share, according to StatCounter. Even if this isn’t entirely accurate, it shows the significant gap in mobile between the engines.