If you’ve been running your own server for a while, eventually you’ll start getting privacy jitters and want to use HTTPS, at which point you’ll either happily set it up with minimal difficulty (if you’re running a single site) or realize frustratedly that you can’t use HTTPS with name-based virtual hosts. To quote the Apache site:
The reason is very technical, and a somewhat “chicken and egg” problem. The SSL protocol layer stays below the HTTP protocol layer and encapsulates HTTP. When an SSL connection (HTTPS) is established Apache/mod_ssl has to negotiate the SSL protocol parameters with the client. For…