The folks at NewsGator share a case study. 

Triple Point Technology has transformed the way they share information within the enterprise. From critical build and release notifications, to internal publishing and collaboration, publishing via RSS has dramatically changed their information landscape.

Michael Sippey summarizes: 

It's not really about weblogs at all, rather it's about how RSS (or whatever you want to call it) can be used to augment typical email- and web-based collaboration systems. Key points:

• Feeds are generated not only by individuals, but also by teams, and by software. They publish the output of their release management system in RSS. They've retrofitted Sharepoint to output RSS streams for watched folders.
• They're driving the posts right into their mail client (Outlook), which is where info workers seem to spend an inordinate amount of time. No need for training on a new piece of software, and power users can customize views to their heart's content.
• The subscription model is much more efficient and user-driven than internal mail archives. A couple of years ago I wrote a piece for theobvious on how I wanted Yahoo Groups for my intranet. The key thing there was (a) discovery and (b) user control over subscription. An OPML directory and user-controlled aggregator solves that problem. No more sysadmin time dealing with "hey, can you put me on this list for the next few weeks while I monitor what's going on with this project?"

If the blog/feed/echo/rss whatever thing takes off inside large organizations, and thousands of people, teams and systems inside companies like IBM or HP or Sun start blogging, there's gotta be a market for the intranet equivalent of blo.gs where users could learn of recently updated feeds they don't subscribe to, find new ones based on existing subscription lists, etc. (Question: is anyone selling software like this today? To slurp up user's OPML files and discover relationships and create an interlinked directory?)

Sippey gets it. So does Triple Point.