A lot of people have expressed distaste for Windows 8's Metro design, so Microsoft has gotten rid of Metro...well, just the name.
The feature formerly known as Metro is the most distinct aspect of Windows 8. It allows users to have complete customization on their home page, including widgets, RSS readers, weather information, date/time, etc.
In addition, since this is such a revolutionary new platform, Microsoft wants to scrap out all remnants of the "old-school" look and feel. Instead of a Start bar, hovering your mouse over that corner of the screen will allow you to swap between the "Metro" UI and the traditional desktop. For the mobile version of Windows 8, that UI will be the default interface.
The software giant is claiming that Metro was a codename all along, even though it has picked up significant traction and has been used by third-party developers to discuss their new Windows 8 projects. Mozilla and Google, for example, have both pledged support for "Metro" versions of their browsers.
Because of this, skeptics believe Microsoft is lying about the codename excuse and instead believe the company became worried about potential trademark issues. A European software company that owns a trademark on the "Metro" name, and the last thing Microsoft wants is to go into a legal battle over something so trivial.
Employees have reportedly been told to immediately stop referring to the new UI as "Metro." For the time being, it will be known as the "Windows 8 style UI."