I missed this article in the Wall Street Journal highlighting enterprise 2.0: Social Studies - WSJ.com ($$). Ironic that I missed the article because I was at the Enterprise 2.0 Conference.
The article tracked my thoughts about the e2.0 technologies. Wikis are the most useful for business because they allow collaboration and they capture the product of that collaboration. Blogs are a useful communication tool for executives and among a project team. RSS pulls it all together by pushing the changes to wikis and blogs to those interested in them.