A subdomain is a web address, 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 website and records i.e. aside from using the domain name as a part of the whole web address, a subdomain can be completely independent and also hosted by a separate service provider. Employing a subdomain can be quite practical if you want to have different web sites that are related in some way. As an example, you could have a web-based store under the main domain and a forum under a subdomain so as to offer means for your clients to ask questions or share opinions regarding your products. The main advantage of employing a subdomain as opposed to a subfolder is that the web sites will be separated, so you can update one of them or perform maintenance without affecting the other.