1. Hosting Basics
Things you put in a public_html subdirectory of your home directory are accessible via http://hcoop.net/~you/, and in general ~you on any hostname that has the same front page as http://hcoop.net/.
If you want to host a domain with standard services like HTTP and e-mail, see DomainRegistration and DomainTool. If you want to host a miscellaneous daemon, then request a firewall rule for it by submitting the appropriate support ticket from the Portal Security page.