Sub Domains & SEO | Optimising a website sub domain

Sub domains are an extension of a domain name that will typically form before the domain name, and will be separated with a full stop. Sub domains are treated as independent websites unless they are heavily linked between the parent domain.

Sub domains are incredibly popular for large scale businesses and commercial websites that have a large product array. Sub domains can be optimised independently but can also be a part of the leading domain inheriting page rank and authority.

There are lots of ways that sub domains can be beneficial, at the same time, if used in the wrong manner sub domains can potentially affect the performance of the top level domain. Sub domains will appear in a fashion similar to http://mysubdomain.domain.com. Most sub domains avoid the use of www. Protocols because of the connection from the root level of the domain.

Sub domains will usually be hosted on the same server, its important to know that hosting a sub domain on a different server can actually have a draining factor on the top level domain. Many different configuration options are available to prevent this, but in general, it will have an impact.

Sub domains are utilised to split up a website into different categories or product bases, which is ideal for businesses looking to separate different sections of their website.

Utilising sub domains properly however can bring many benefits including enhanced ranking placements for various different keyword groups and themes rather than a domains general approach of core keywords on the home page and sub pages being returned for the appropriate keyword search.

Sub domains should contain unique content, and should maintain a good internal link profile, having a poorly utilised sub domain can lead to trust issues with top level domains unless the sub domain is separated from the root domain with nofollow attributes.

Sub-Domains and the Selection Process

When sub domains were introduced by registry foundations such as Nominet, they were often abused by adding in lots of different keyword groups into the URLs and then re-directed to the top level of the domain, which actually led to the decline of many popular websites. Sub domains are a separation factor only and should not be abused in order to enhance rankings.

Be careful not to link too heavily between domain and sub domain, because the sub domain is treated as an independent website, it could be seen as excessive intra site linking, which can become detrimental towards rankings for both the domain and sub domain.