Copyright of a Category Structure?

[zulufox]

I am trying to build a great category structure for my site and it appears that dmoz has done it for me.

Is it legal for me to use a slight alteration of their category structure?

Can you even copyright a category structure?

Could I use another sites category structure, like ehow?

[diamondgrl]

Dmoz is an open source program so I imagine it's fair game. You would have to check their licensing agreement to be sure. However, other categorical schemes can have copyright protection.