"On demand" originally denotes "pull" reporting; it suggests that decision-making information can be generated or retrieved at will. More recently it is often used to connote SaaS.
"On demand" originally denotes "pull" reporting; it suggests that decision-making information can be generated or retrieved at will, as opposed to a scheduled "push". (This correlates historically and functionally to the "just in time" model of supply chain management that became popular in the 1990's.) The term has strong marketing appeal and now is used to suggest convenient application deployment or SaaS. This value for branding purposes has created ambiguity in usage.