In pervious versions of 5, 6, 7, 7.5 etc we have always had the ability to host multiple web sites under same IP address/port using HTTP/1.1 virtual hosting, i.e."Host Headers" where the web server looks at the DNS address entered into the Internet Browser and forwards the user to the appropriate site. Of course if a user accesses a website by IP, the Host Header will not work.
IIS has supported utilising Host Headers for HTTPS sites also for quite some time, however this has always been harder to configure with manual editing of the IIS metabase being required in previous versions of IIS, see http://clintboessen.blogspot.com.au/2009/03/how-to-setup-ssl-host-headers-iis6.html. However although SSL Host Headers were supported there was one problem which administrators faced. There was no way to sign a different digital certificate for each HTTPS website.
Now with IIS8 in Windows Server 2012, a new feature has been added tha extends the SSL and TLS protocols to indicate what hostname the client is attempting to connect to at the start of the handshaking process. This allows the IIS8 server to present multiple certificates on the same IP address and port number and hence allows multiple secure (HTTPS) websites to be served off the same IP address without requiring all those sites to use the same certificate. Multiple digital certificates assigned to the same the same IP/Port - very cool.
I'm sure we will see many changes to applications which leverage IIS adopting this new technology.