I wrote a blog post of things that directory owners should keep in mind when they create a category structure here I would love to hear comments on my views and other things that I may have missed. I have to admit I am still in the learning process when it comes to directories.
I checked out your blog, pretty good stuff. I have a link to my web design website from all of bob's directories spoke to him a few times on the phone he's a cool cat. Funny you should bring this up I was just looking into this. So here is a question for you. What do you think is the most popular subcategories for these top level categories? Health, Business, Shopping, Internet(exclude: directories, web design and seo), and Recreation. I only want to list 3 most popluar for each one.
Health is a bit difficult but I would say Beauty, Nutrition/Fitness and Pharmacy Business is easy Real Estate, Law, Investing Intenet is not difficult but they are the ones you told me to exclude for example check the directories category at Alivedirectory. Other than that in a high PR directory I believe that domain names and hosting could attract a lot of submissions but not in a low PR directory. Shopping: Gifts, Electronics and Toys but overall I believe that shopping is one of the categories that needs a lot and I mean alot of subcategories. For recreation Travel is for sure the most important subcategory, after that it's the hobbies probably and the humor/music. However don't take my word on that those are from a limited personal experience.
Any advice would work. Only reason I ask is because like you said we would like to attract alot of submissions, I see alot subcategories are just empty which leads me to believe that there is just not enough people interested in those category. Thanks for the advice.