Bing may have a smaller portion of the available audience for search engine marketing revenue than Google but according to a new study from Chitika Research, its users are more likely to click on ads – a critical part of the PPC model.

Across a sample of some 15 million impressions by web users used by Chitika, Bing users clicked on ads every 1.67% times they viewed the ads in SERPs. This was significantly higher than Google, whose Ad Click Rate was only 1.09%.

Surprisingly, Ask and AOL were the services most likely to see users click through (2.92% and 2.48% respectively). This is despite the majority of ComScore and HitWise reports over the past year assigning them less than 5% of the search market between them.

According to Chitika, this because “Microsoft absolutely did the right thing by targeting people who buy online.” The research company’s co-founder and CTO, Alden Dosario, attributes Bing’s higher click rate with the engine’s integration of e-commerce features early on, particularly its Cashback promotional advertising service. Dosario says that CashBack “ensures that people who were using search with a clear intent to buy came to Bing.”

If Chitika is correct, then the upcoming integration of Yahoo and Bing search engine marketing could have a substantial effect on how the revenue generated in the medium is shared between the “big three” – perhaps, with Yahoo’s wider audience base, Bing’s successful click through rate could be even higher.

Either way it is another promising sign for Bing. According to other, earlier reports from Chitika, Bing has also seen a considerable rise in its share of the audience over this quarter, rising steadily from April (4.4%) to mid-July (6.6%). At the same time Yahoo has made less impressive but significant gains, reaching 5.9% from 4.9% in the same period.