Martin has a post asking (and attempting to answer) the question What is a Blog Network? which might be of interest to some. It includes a very rushed and un-thought through response from yours truly.
I’m not really sure there is a single definition for a Blog Network – if you look at the range of them out there – they certainly come in all shapes and sizes and have a large variety of practices, values, purposes and formats.
But if definitions are you thing – head over and have your say.