Recommended: You probably want a Domain Name
While not technically "required", it's a good idea to have a domain name to set Jamroom up on. If you are running your own server you can run Jamroom on a bare IP Address, but that's not going to apply to most of you.
You'll want to either have an existing domain you want to use, or purchase a new domain to run your site under.
If you are looking for a quality domain registration company, we recommend Namecheap