You can make any number of local websites. “Locality” is determined by the domain name. For example, localhost, site.localhost, mysite, mysite.local, 127.0.0.1, 192.168.168.150, my-love-site.www. Any address as IP is also considered local and doesn’t count.
If you activate a website on a subdomain which address looks real (not another “localhost”, that is), then the main domain of this website will be added to the list in your account.
So, for example, you can use following addresses:
All of the above addresses will be counted as just ONE “site.com”, so subdomains are not counted, only main domains are. You can manage the list of your websites in the personal account.