A subdomain is a website url, which is under a main, or a root domain. An illustration is something.domain.com, where domain.com is the main domain, while "something" is the subdomain below it. Each and every subdomain can have its own site and records i.e. aside from employing the domain name as part of the whole web address, a subdomain can be totally independent and also hosted by a separate service provider. Using a subdomain can be extremely beneficial if you wish to have different web sites that are connected in some way. As an example, you may have an on-line store under the main domain plus a forum under a subdomain in order to provide means for your customers to ask questions and share views regarding your products. The benefit of employing a subdomain instead of a subfolder is that the sites will be separated, so that you can update one of them or perform maintenance without affecting the other.