FirearmsTalk just made a major change.
They created a new forum for every US state, listed alphabetically.
They had a lot of demand from members, they claimed.
The problem with top-down community planning is the planner makes these sorts of mistakes.
The community is now dissipated across 50 categories. Some will be heavily used (see Texas above), others are unlikely to see much activity. The popular categories like Texas are buried way down the list (behind Hawaii, Maine, New Hampshire, and Rhode Island.
There is a right and wrong way to grow a forum. Top-down planning usually isn't the way.
You don't need to treat every US state (or any category) equally.
You need to respond to interest. If you have a lot of people from Texas in Firearms talk, you create a category for Texas. If you have a lot of members for North Carolina who want to connect with each other, then create a category for North Carolina.
If you have a lot of people interested in a specific firearm, then create a category for that firearm. But don't create a category for every firearm.
Keep the community activity as concentrated as possible and create new categories when the need and demand arise.