There's now a multi-author weblog tool for Radio. It's pretty damn cool, and an interesting way to do it. I've been looking at weblog software that has the concept of multi-author blogs. One thing I like about them is they provide a more interesting way for people to collaborate. For instance if you have a blog for a product-line you are working on, you can have everyone involved have posting access to it.
Glancing at this tool, it looks like you could even have contributers to the weblog who aren't running radio, since it uses RSS.