Is Microsoft really planning to sell a branded smartphone? I’d be surprised to hear otherwise.

Indeed, as the company prepares for what might be the most critical series of announcements in its 37-year history, the question isn’t whether it’s planning its own Windows Phone. Rather, it’s what Microsoft hopes to gain by releasing it.

All the smartphone buzz is coming to a head even as some PC vendors are still trying to understand why Microsoft is selling Surface, its own family of tablets built around Windows RT, the iterant of Windows 8 for ARM processors. Many of the PC suppliers are also producing Windows RT tablets, and the notion that Microsoft would be competing with them is tough to swallow. The Surface tablets–as well as many of the other RT devices–will be available on Friday, which is also the first day that consumers can take home Windows 8-based PCs from Microsoft’s hardware partners.

Microsoft’s Windows Phone 8 devices similarly would compete with smartphones produced by Microsoft’s hardware partners. So after decades of producing either peripherals that complement its partners’ products or proprietary platforms in non-PC markets–such as Xbox and Zune–Microsoft’s hardware portfolio soon will sport two devices that battle its partners’ offerings. The burning question: Why has the company decided to cross that line?

Read the entire column on InformationWeek.com.