Yeah the corporate intranet is pretty incredible, hard to imagine working without it now. More or less every office worldwide is connected. (Though there are a few outposts that still RAS in)
It has moved a long way ahead from everyone having mapped drive letters to files stashed on a few shares.
IIS was a huge turning point in delivery of project websites.
The Sharepoint/Office combination added to that by enablin authors to broadcast their publications without developer experience. Add corporate webcrawling and suddenly the rest of Microsoft can find your project's current status, features etc. in a snap