Please consider this a quick PSA (Public Service Announcement) as it is still common that I run into environments with the IIS SMTP service still running and processing mail.
While the component has had a long and interesting life, it is now unsupported as it is tied to the support lifecycle of Windows Server 2003.
For more details and information please see:
How to: Install and Configure SMTP Virtual Servers in IIS 6.0
The only thing you (MS) will achieve with that, is us moving to linux. Who would want to change one SMTP service, a small windows component, for a giant Exchange server with lots of services and why?
Is it really that hard for a corporation as big as MS to keep such an easy component in support lifecycle?