How to use a blog (for non-bloggers)?

I suggested an internal team blog a while ago and was quite alone with that. We then started anyway, and now, a few weeks later, the discussion is on what blogs should be used for.

• Are they a tool to present and discuss ideas and innovation?
• Are they a convenient publishing tool, to publish and eventually discuss information for a broad audience (meeting minutes, open feedback requests)
• Should they be used for collaboration, to request feedback, to distribute drafts of documents we are working on?
• Should they inform on current issues beyond the official internal newschannels?

There are many more questions and many more ways to ask the same questions.
what I really wonder: If you are running a blog as a team (and not because there is one such prolific interesting writer) - do you really have to define all that?

• You won't be - according to my experience - overwhelmed with content.
• Everybody who really starts to work with a blog instead of thiking about it will quickly develop his way of using it.
• Trying to define such guidelines often leads to the discussion on how to structure the different contents you defined. People start to discuss folders or overview-pages they want - and this is where the discussion definitely leaves the area of blogging. A blog is not the cure-all for everything.

Sometimes it might be still smarter to juist use "normal" publication channels. Not using a blog in some cases can also help to discover the benefits and advantages of blogs.