I've been thinking about shifting at least some of my communications from e-mails to blogs especially in the context of business communications.
Blogs are pull rather than push, so I'm not innundating other's inboxes. People who are interested in the projects or topics I'm working on can subscribe and consume the content as they wish. Also it's a way to be more expressive since it's a medium where ideas can be connected to provide more relevant context. That doesn't mean chats and even e-mail couldn't be used for urgent communication. For async non-urgent communciation though, blogs might be a good alternative to e-mail.
These two articles provide a good introduction into how individuals and companies have implemented similar practices: