Yes you are making 2 websites. The one on your own computer is considered a testing site. The one you can try adding new things without having to worry if you break it apart It's a standard practice - you never know if the new add-on you download will work. It might break your website apart. So it's always nice to have another copy to try it out. It's not necessary. But imagine, your real forum is up and running. And you have quite a number of members joining. Do you want to risk trying new things right onto that forum? With no guarantee?