Why not use HTTPS for everything?

Question

If I was setting up a server, and had the SSL certificate(s), why wouldn\'t I use HTTPS for the entire site instead of just for purchases/logins? I would think it would make

Answer 1

windows Server 2012 with IIS 8.0 now offers SNI which is Server Name Indication which allows multiple SSL Web Applications in IIS to be hosted on one IP Address.