What about adding sub categories? That would be very neat. For instance... say that you have a site with IT related articles. You might want to review a whole lot of products, or just build a product library. Then you might want to divide it in some main categories like Processors, HDD, Graphic Cards, Sound Cards, Speakers and so on. And then you wanna add "sub categories", maybe sorted alphabeticly, wich in real time can be diffrent brands and manufactures like Samsung, Sony, Asus, Kingston and so on...
In That case you would be able to build a product library.