How’s this quote: “Intranets are unique providers of content. Although the audience is captive, the content still needs to engage the readers so the site becomes a useful and vibrant center of a company’s internal community.”
This is from a nice article: How to Develop an Internal Content Marketing Plan by Leveraging Intranets. So in other words, using the ideas of good content marketing that are used on public web sites for intranets and employee sites.
Good content is good content. Regardless of where it is or who it is aimed at. Unfortunately though intranets can be a dumping ground within companies for content that is just there for the sake of it or to tick a box. Or that the standard of writing is not what it should be. I mean, have you ever read a policy before? Awful stuff.
Have a look at some intranet design winners to see what is possible. If you work on an intranet (and I do) you don’t call developing and promoting your intranet as ‘content marketing’ but it’s pretty close.