I thought this would be a fun post to do because Microsoft does a lot of things, but they are just one company. Well Microsoft is a platforms company, this means that they make software that other people and organisations can use to build their own stuff ontop of.
Here are some examples of the platforms they make:
Win32
Been around since Windows95 and is the basis for all windows applications. If an application is funning on windows like Microsoft Office for example, then it is running ontop of Win32. Or possibly Win64 if you have the new 64Bit XP OS.
GDI/GDI+
This is apparently most of what you see on the screen. Windows forms and everything rendered inside Internet Explorer sends data to GDI with then produces something that can be sent to your Monitor.
GameSDK
Later renamed DirectX, this platform is a standardised interface for 3D hardware, input devices and sound hardware, specifically designed for use with games.
.Net
I will probably do a post on this in the future, but it is a new platform for creating and running software.
Avalon & Indigo (the future)
Avalon is best described as software for people, as in 3D interfaces for websites and software. Avalon has the potential to destroy the market capabilities of flash as the custom interface standard. And Indigo is best described as software for software, as in distributed services. So with that Indigo could have a company database on the other side of the world, but interface with it as if it was local with software developed inhouse or by a completely separate company.
XBox (and to my real point)
With the Xbox Microsoft was apparently new and uninitiated into the console market. And that would be true if you looked at the gamesconsole as products, but Microsoft seen a platform. And as a company that builds platforms, Microsoft has been doing this a lot longer than everybody else.