The closed-platform style of an intranet (not to be confused with the internet) allows for secure distribution and communication of information within a company or organization. In the good ol’ days (a decade ago) company intranets were extremely useful in transferring data, sharing files, and collaboration.
Today, it’s much less useful. The speed in which information is able to travel with today’s technology makes the intranet a much-less valuable part of the business world. Still, it’s not dead, and as more exploits are found to gather data from companies using internet-only protocols, there should be a resurgence of closed intranet systems.