Art --> @directory (points to Art(below) and is not a real category, just a pointer reference to it.) Internet --> Directories --> Art (is the real category)
as an0n said say you have a category called Arts and a Directory sub category under Arts you also have a category called Niche Directory now you can create a symbolic category under Niche that say @Arts Directory this will link to the Arts Directory under Arts
The design is as Anon said. Think about how you would look for an Arts Directory on another directory. Since you are a directory owner, you would probably look in the Internet > Directories tree first. Someone who has an art site might follow the Art > Directories path instead. It is simply a way to have a single category "appear" in more than one place to make it easier for site visitors to find what they are looking for.
"symbolic category" is a category that points to another category. its like a shortcut on your desktop to some program in your program files. symbolic category can not have any links or articles since its just a link to another category. new category is a regular category, with links and articles in it.
Example http://www.abifind.com/cat/Health_and_Fitness/ Alternative Medicine is a regular category Disabilities is a symbolic category
in fact, you give your own answer. new category: you are adding a new category for one of the option. symbolic category : you are choosing a category from the existing categories. not adding a new category
a "symbolic category" is NOT a category, it's a reference pointer. You cannot peer into a symbolic category You cannot have sub categories within a symbolized category.
thanks for clearing this up! even i was wondering what exactly is a symbolic category! so it's just a pointer to guide you to the more accurate category!!