Example of a virtual domain
This is a virtual domain because the owner of the domain resides in Arkansas, but the server that host the site resides in Washington. The hosting company, webintegrity.com provides this same hosting service for many companies, not just scobb.com.
Example of a non-virtual domain
This is non-virtual because Mid-South Community College self-hosts their own website on campus, and does not host any other domains.
Example of a sub-domain
http://assessment.midsouthcc.edu/
Sub-domains also share the domain name of the primary host, but instead of a / path following the .com, the department, division of company name precedes the primary domain name. Sub-domains are most common within companies. For instance, in the example above; the url will point to the Assessment sub-section of the midsouthcc.edu website.
Example of a shared domain
http://www.angelfire.com/musicals/m_hay/
This is shared because many individuals and non-profit organizations can host with angelfire.com. Each site will begin with the domain name www.angelfire.com, but the path following the .com will vary. This is common in free hosting options. If you signed up for a free website at www.geocities.com, your url would be in the following format: www.geocities.com/your-Yahoo!-ID
Most businesses prefer to have their own domain names rather than a shared domain. Having ones own domain name is more professional.