Now we know why reports surfaced last month indicating that Apple (AAPL -0.81%) was in talks with the major record labels to introduce a streaming music service.

It wasn't that the world's most valuable tech company was gunning for Pandora (P) or Spotify. The class act of Cupertino had a much bigger and familiar fish to fry: Microsoft (MSFT -0.66%).

Xbox Music was introduced this morning. Microsoft's full-featured digital music platform hopes to bridge the elements of Pandora, Spotify, and iTunes to create a one-stop hub for music discovery, playlist streaming, and MP3 purchases.

The service will roll out to Xbox Live console gamers tomorrow. It will also be made available to buyers of Windows 8 PCs and tablets -- as well as mobile handsets powered by Windows Phone 8 -- later this month.

In a nutshell, Xbox Music will come preinstalled as the default music player when Windows 8 rolls out during the final week of this month. It will feature ad-supported streaming of a 30 million song catalog at no cost. Users can discover new music (like Pandora), make playlists of individual tracks that they want to hear (like Spotify), and purchase MP3 downloads (like Apple's iTunes).

An Xbox Music Pass will be available for $9.99 a month for users that want greater cloud-based portability and enhanced features.

It's true that Microsoft hasn't had a lot of luck with digital music (Zune, anyone?). It's also true that services are quickly evolving into jack of all trades. Spotify recently rolled out a Pandora-like music discovery platform. Even Sirius XM Radio (SIRI -1.59%) has fortified its digital offerings. The satellite radio monopoly rolled out on-demand streams of some of its more popular proprietary content this summer and will roll out its own Pandora-like service by the end of the year.

You still have to like Microsoft's aggressive move here. If the service proves popular -- and admittedly that's a big if, given the company's history with consumer products and services outside of Xbox's success -- it will encourage PC owners to upgrade to Windows 8 and entice smartphone and tablet buyers to consider Microsoft's operating system in lieu of Android or Apple's iOS.

We'll begin getting the first wave of critical reviews when the service rolls out to diehard gamers tomorrow. Microsoft know what's at stake, and Apple has to be ready in case in actually needs to respond here.