According to Adam Bunn, the company's director of search, the idea is that instead of searching for a website that can answer a question, smartphone users will prefer to find and install apps than can answer that and similar questions.
"To maintain any kind of grasp on the mobile user, search engines will need to be able to point out apps that might be relevant to the searcher's search - and even give them a one-click install option for when the search is being carried out from a mobile with the right operating system. This will manifest as another type of vertical search on Google and Bing, as well as being pulled into the normal results as a universal search element," said Mr Bunn.
This makes some sense from a user's perspective, but doesn't really consider the motivations of the search engines themselves.
The basic model is that search provides an opportunity to deliver relevant advertising. But if the search engines divert future searches to apps, they transfer advertising opportunities away from their own web interface and towards the individual apps.
But given that one of the problems with the (iOS) App Store is finding products in the first place (niche products can easily be buried by popular ones), the idea does have merit providing the companies are prepared to be altruistic. It wouldn't be very helpful if Bing only returned Windows Phone 7 apps, for example.
And if they were going to do it for mobile apps, why not include desktop software too? Admittedly there's less chance that there would be a program that corresponds to a search request, but there are examples. For instance, someone using a Mac to search for "weather forecast australia" might benefit from seeing links to TheBOM Weather Widget and similar pieces of software.