Help Desk
A point of contact for users to report issues or ask questions. Historically focused on "fixing broken things," the term is often replaced by "Service Desk" which implies a broader, more service-oriented role.
Impact
The Help Desk is the face of IT to the user. A poor help desk experience destroys the reputation of the entire IT function, regardless of uptime.
Weinto take
"Help Desk" implies helplessness. We build Self-Service Platforms. Users shouldn't have to ask for help to reset a password or provision a server; they should be able to do it themselves via a portal or API. The best effective Help Desk is one you never have to call.