By Avelyn Austin
Apr 8, 2009
More Articles by Avelyn
“In the Domain Name System (DNS) hierarchy, a subdomain is a domain that is part of a larger domain. For example, “mail.example.com” and “calendar.example.com” are subdomains of the “example.com” domain, which in turn is a subdomain of the “com” top-level domain (TLD).”
Large companies or institutions with smaller brands operating under its umbrella are ideal candidates for the use of subdomains. For example, let’s analyze the fictitious “University X”. “University X” is the umbrella brand for the individual school brands (i.e. the Business school at University X, the Communication school at University X, the Education school at University X, etc). With so many smaller brands operating under the University X brand, they would be wise to set up a subdomain for each of the schools. Therefore, in addition to having UniversityX.edu for the entire university they should also have Business.UniversityX.edu for the business school, Communications.UniversityX.edu for the communications school, Education.UniversityX.edu for the education school, etc.
The number one reason to use subdomains is to “own” the search results for highly relevant keywords. For instance, if someone searched on the term “University X”, it would be best if the results page contained multiple listings pointing to one of the University X sites. Because search engines see directories (UniversityX.edu/DIRECTORYforexampleBusiness/) as part of UniversityX.edu domain they will typically only serve one search result that points to that domain, where as subdomains like Business.UniversityX.edu are seen as separate sites and may appear on the same page of results. Thus, University X can “own” the search results, gaining maximum visibility.
For all you Brand marketers, another reason to use subdomains is to promote the small brand while simultaneously promoting the BIG brand. How do subdomains accomplish this? Link building is a huge factor in a successful SEO campaign and thus it is important for links that are built toward a site benefit the rankings of the small brand as well as the BIG brand. Thus, a link built toward UniversityX.edu/Business would greatly benefit the rankings of UniversityX.edu; however, would benefit the Business directory/site only slightly. On the other hand, a link built toward the subdomain Business.UniversityX.edu would greatly benefit the business site as well as benefit the UniversityX.edu site, killing two birds with one stone.