You can use your own domain name (like someawesomename.com or subdomain.someawesomename.com) instead of using a subdomain of popforums.com (like meta.popforums.com). To do this, you'll need to register the name with a domain registrar, then set a few DNS entries that point to POP Forums. Domain name registration and DNS is beyond the scope of support here.
Only certain plans support custom domain names (see pricing). If your plan supports custom domain names, contact firstname.lastname@example.org for more information.