Microsoft CEO Steve Ballmer released his annual letter to shareholders, customers, partners and employees yesterday and offered some guidance on what we can expect from the company over the next few years.

Most notably, the executive acknowledged that there's a fundamental shift underway with regards to what Microsoft does and how it sees itself, noting that they're not just a software company anymore but rather a services and devices company too.

This isn't an overnight shift either. Despite historically relying on other companies to make hardware for their software products, Microsoft already successfully ventured into gaming hardware years ago with the Xbox 360, and less so into music hardware with the Zune, along with the cloud-based services around them.

These are areas where their partners usually aren't directly involved, however. With the Surface announcement in June, Microsoft showed it's not afraid to upset a few partners by building its own tablet if it feels it needs to lead the way or that others are falling short. Ballmer's emphasis suggests an increased focus in end-to-end hardware, software and services products, much like what Apple does today.

Of course, hardware partners will still be a big part of the picture to deliver a broad spectrum of Windows PCs, tablets and phones. Ballmer says "there is no way one size suits over 1.3 billion Windows users around the world," but when it makes sense they'll build specific devices for specific purposes.

You can read Ballmer's letter in its entirety on Microsoft's website.