SSL or Secure Socket Layer have been used for a variety of different services such as Linux boxes, FTP servers, even webmail and banking sites. According to research from Qualys, a security research firm, out of 119 million domain names scanned, 92 million were actually active, 12.4 million of the remaining domains failed to resolve properly, and the other 14.6 million gave no response at all. Out of the 92 million active domains, Qualys shows that 34 million domains use both port 80 (typical HTTP port) and port 443 (typical HTTPS/SSL port).
While those numbers do not seem to strike any significant problem, it seems only 23 million actually use SSL. The cause for concern comes about when discussing SSL certificates. The bigger picture shows that only 3.17% of the 23 million servers have valid certificates. This problem comes from domains generating certificates with the the incorrect domain name. According to Ian Ristic, director of engineering at Qualys:
"We have about 22 million SSL servers with certificates that are completely invalid because they do not match the domain name on which they reside."
Essentially what this all boils down to is many sites that have SSL built in to their infrastructure are not gaining the benefits of the security it adds due to the invalid or improper domain name.