Jakob Nielsen sounds off on better web design. Interestingly enough, he doesn't mention blogs per say but he does the goal is to limit what needs to be in an email from a corporate standpoint. If you believe that concept, run, don't walk and pick up the Simplicity Handbook (http://www.simplerwork.com/handbook.htm) because Bill Jensen suggests deleting 75% of your new email as a way to become more productive. Funnily enough, the approach actually works. Bill also has great ideas for making your emails more effective.
Now, who's to say how Nielsen regards RSS feeds but the fact is, using something like NewsGator (which makes new blog posts appear as emails), it simply makes it an easier search mechanism (especially when combined with Lookout).
Sadly, the issue with making intranets more useful is NOT having more intranets - the problem I have found is with the people. That's why blogs and wikis are so valuable. I can easily find out what people are up to by reading their blogs. No blog? I don't want to read a status report (ugh!). Nielsen may be good at saying what's wrong - but he needs to give better insight into why people don't use intranets. (hint: It's NOT because of PDFs,popups and searches - it's because they don't want to have to go somewhere else).