I'm a student, so I don't have enough time (and probably don't know enough) to maintain my own blog, but I would love to write an article or two once in a while.
Also, discussing articles with other contributors before publication sounds like a great way for me to improve my own writing quality--it's like free editing.
What do you (and other interested people) think the minimum number of contributors is? How many people would make something like this both interesting and lasting (e.g. people continue publishing posts in the far future)?