What is the significant difference between Windows server 2008 and Windows server 2012?

Active Directory Domain Services (AD DS) in Windows Server2012 includes new features that make it simpler and faster to deploy domain controllers (both on-premises and in the cloud), more flexible and easier to both audit and authorize access to files with Dynamic Access Control, and easier to perform administrative tasks at scale, either locally or remotely, through consistent graphical and scripted management experiences.
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I THINK ITS FLEXIBLE 

FEATURES WITH INBUILT GPMC

INBUILT ACTIVE DIRECTORY RECYCLE BIN FEATURES 

IIS 8  IN WINDOWS SERVER 2012

What's New in Windows Server2012 :http://technet.microsoft.com/en-us/library/hh831769

Following are some of the better features of server2012.1.SMB3.02.Better Hyper-V (more virtual CPU, memory) and new feature of Hyper-V replica,3.VDI.4.simple licensing5.NIC teaming6.Better bit locker.7.Works better on limited hardware resources.
And many more.....