Haskell.org sub-domains are hosted on a variety of machines. Various machines have individuals responsible for them, and various services in turn have individuals responsible for those services.
In general, the policy on the usage of the Haskell.org domain name and subdomains is set by the Haskell.org committee. The committee also manages a small amount of funds, generally garnered from Google Summer of Code payments, and uses them towards the maintenance of Haskell community infrastructure. It therefore also determines the policy on the uses of those machines that it pays for.
Many people responsible for managing and helping with maintenance of Haskell.org servers are aliased at "admin [at the domain] haskell.org".
If there are problems with infrastructure, it is good to check status.haskell.org to see if they are already known. If not, emailing the admin at h.org mail alias and the #haskell-infrastructure irc channel on freenode are all good ways to get in touch. Automated uptime and status information is provided at auto-status.haskell.org.
The centralized location on infrastructure is now maintained at the Haskell Phabricator Wiki, cataloging machines, responsibilities, etc.
See also: Haskell Governance