Microsoft had used the old logo for 25 years, 4 rectangles with different color, followed by ‘Microsoft’ name written in Italic. Following their plan to launch the new version of Windows, Windows 8. And other products that will be released, Microsoft introduced their new logo.
Now, Microsoft have 4 triangles -people know it as their trademark- with different color, and their company name beside it, the most used operation system in the world. Simple, first sight when we are looking into the new logo.
Microsoft looked very excited to release their products, they stated that the logo was not only a re-imagining of their products, but also a sign for a new era of Microsoft. They also said that it was just a beginning.
You can check the complete statement here.