I would ask myself the following questions:
- Does the audience you are addressing already have a "home"?
Your primary goal shouldn't be to run a forum for the sake of running a forum. Your primary motivation should be to give your community a home.
- Can you reach initial traction?
How many readers do you have? How many of them do you think will contribute to the forum? Your blog seems to be pretty popular. Why don't start with one category and see how it develops?
Looking at your blog, I don't think that this will be a problem. Nevertheless, you need to be prepared to spend quite some time answering questions in your forum yourself.
When in doubt, fake it 'til you make it. That's how reddit got started: By creating massive amounts of fake accounts and posting everything they found online.
Here are a few "golden rules" on running a forum:
- Don't start with n different categories.
Start with one instead. See what people are talking about. If a category becomes to cluttered, add a new one.
Don't try to structure your forum before you have content!
- Ask users what they want.
- Define the scope of your forum.
What should be the primary topic people are supposed to talk about. An off-topic board is ok, but it'g good to have a general idea on what your community is supposed to look like.
- Sign up beta users first.
It's probably a good idea to start with a small core group before launching and inviting everyone. People won't post in an empty forum, because they think it's dead. By starting with a small core audience, you have two advantages:
1. They feel special because they are first. 2. They KNOW the forum is empty, but NOT DEAD.
However you decide, good luck! Running a community is tough, but a lot of fun.