According to today's post about the new logo on the Windows Team blog, Microsoft's goals with the Windows 8 logo were to make it both modern and classic; use "bold flat colors and clean lines and shapes": and meant to align with the fast-and-fluid Windows 8 catch words.
When users change their background color, the logo will change color, too, according to the post.
Update: As several folks on Twitter have noted, it would seem that the existence of an official logo calling the product "Windows 8" would imply that Windows 8 isn't just a codename, but also is the final name of the next Windows client release -- something many of us have expected for years.
Microsoft officials have been quick to note that Windows 8 was only a codename, at least up until today. I've asked to see if we can get an official confirmation that the final name of the product will be "Windows 8." I'm doubtful I'll get such a definitive statement, given the "no comment" policy of the Windows team on even the most seemingly mundane matters. If I do get a response, I'll add it to this post.
Update No. 2: Microsoft officials are not commenting on whether or not today's logo means Windows 8 will be the final product name for x86/x64 and ARM/SoC versions of what is still being called officially the product codenamed "Windows 8."