Intranet sites are websites which are for the eyes of your business only.  Intranet sites are useful to share and work with client information over a network.

Intranets differ from traditional application programming as the program is installed only on your webserver.  This simplies updating the software as it only has to happen in one place.  This makes it much easer for everyone.  No need to run updates for special programs and more.

SharePoint is an excellent tool which allows users to share information and work with documents together.