A subdomain is a web address, which is under a main, or a root domain name. One example is something.domain.com, in which 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 part of the whole web address, a subdomain can be fully independent and also hosted by a separate company. Employing a subdomain can be quite useful if you'd like to have different websites that are related in some way. For instance, you may have an on-line store under the main domain along with a forum under a subdomain so as to supply means for your clients to ask questions or share views about your products. The benefit of employing a subdomain as opposed to a subfolder is that the web sites will be separated, so you are able to update one of them or perform maintenance without affecting the other.