We have a website that is a subdomain of our primary domain, such as
site.example.com. The official URL of the website is
http://site.example.com, but some people keep referring to it as
I have a redirect rule in place to redirect
site.example.com, but I ultimately need to explain why
www.site.example.com is bad practice (or is a bad idea), but I don't know how. Are there any guidelines or rules that dictate best practices with regard to domain names, specifically the use of subdomains?