It is actually possible to serve multiple virtual hosts from the same IP (http://en.wikipedia.org/wiki/Server_Name_Indication#The_fix http://en.wikipedia.org/wi

It is actually possible to serve multiple virtual hosts from the same IP (http://en.wikipedia.org/wiki/Server_Name_Indication#The_fix http://en.wikipedia.org/wiki/Server_Name_Indication#The_fix). The first technique is called Sever Name Indication, which is a way to specify a virtual host with TLS (https) negotiations by sending the virtual domain as part of the TLS negotiation The second method is a specification that introduces the subjectAltName field which allows one cert to be used across multiple subdomains (for things like wildcarding). This would make it really easy to do organization-based subdomains with TLS encryption. There are limits to which browsers and which servers can do it. It requires IE7 and up (not on XP though), and basically all recent versions of other browsers. Edit: noted that IE on XP doesn't work.