It depends. You are referring to the multi domain ssl certificate (commonly referred to as UCC or MS Exchange ssl certificate). Each domain name is referred to as a subject alternative name (or san for short). Sans can either be intranet or fully qualifed domain names (fqdn). If any of the sans are fqdn, then the cert can be used in a global environment for that domain. Intranet sans are not publicly available, thus they cannot be seen on the Internet.