The internet's domain name system (dns) allows for * to represent all possible subdomains of a given domain name. We use wildcard dns records to direct all subdomains of fed.wiki.org to a single server, a wiki farm.
Wildcards are often misunderstood even by implementors of domain name servers. wikipedia 
The Internet Architecture Board (IAB) encourages caution using wildcards for anything but single services and only with the understanding of limitations by the users of the service. report
The mechanism that allow readers to Submit Changes depends on the ability to create subdomains dynamically.