Microsoft CEO Steve Ballmer made an appearance today at RIM's BlackBerry World conference to announce a new partnership between Microsoft and RIM to bring Bing searching to BlackBerry. As a result, new BlackBerry smartphones and the PlayBook tablet will default to using Bing for search and mapping.

The partnership will cover both applications and deeper integration. The Bing for Mobile BlackBerry App, which sports a windows Phone 7-like Metro-style interface, will receive prominent promotion and positioning in the BlackBerry App World store. The application was demonstrated on a BlackBerry Torch 9800, so unlike BlackBerry 7 OS, it will be available for existing handsets.

On new devices, the Bing-powered mapping and searching will be built in to the operating system rather than discrete applications. Longer term, the companies plan to create an augmented reality application fusing maps, location awareness, photo searching, and more.

The move highlights the contradictions a company like Microsoft faces. Microsoft wants to promote Bing, as the search engine is the company's main weapon against Google. On the back of heavy advertising and promotion—as well as regular updates and new features—Redmond's "decision engine" is slowly starting to take market share from Google, especially in the US.

The company is using Bing applications as a way to drive this increased usage and to try to ensure that Google does not achieve the same dominance in mobile as it has achieved on the desktop. The apps for iPad, iPhone, and Android have been generally well-received, and the greater exposure both to the brand and the underlying capabilities of the search engine is likely to win over new users. The partnership with RIM, along with similar partnerships with Verizon, Motorola, and even Nokia, will expand the visibility of the search engine further still.

The flip side to this is that Microsoft has a smartphone platform of its own—a platform that is struggling to make a name for itself in a crowded and competitive market. Windows Phone of course has Bing integration of its own—which works very well—but certain aspects of this integration have been overshadowed by the applications available for non-Microsoft smartphones, as they offer capabilities—including OCR searching, barcode scanning, location-based reminders, and more—that the built-in Windows Phone integration lacks.

In producing these applications, Microsoft may well be helping Bing—but it's equally making Windows Phone compare unfavorably with the competition. With both Windows Phone and Bing being strategically important, managing this overlap without damaging either product is going to continue to challenge the company.