Intranets and extranets are based on the same underlying technology as websites; however they tend not to be publicly accessible. Intranets are often used by organisations as an internal online resource whereas extranets tend to extend access to a larger audience (e.g. suppliers, clients, stakeholders) via the web.

Although used in different capacities, intranets and extranets have similar purposes. They are mainly used to improve communication and to pull together a variety of information into a single cohesive interface; information that may have historically been available in a variety of different formats and places.