8. A system comprising: a processor; one or more memory devices; a data store held in at least one of the memory devices, the data store comprising: rule definitions, each rule including one or more rule components, each rule component including a reference to one or more values from which an inference is made when the rule is applied; tag definitions which when associated with a rule component limit how the rule component may be modified, the limiting of one or more rule component modifications with the one or more tag definitions including a tag definition specifying a subset of available rule component values from the one or more values defined in the rule definition, the tag definitions each including at least one verb that identifies how the tag modifies data of the available rule component values to form the subset of available rule component values; associations of tag definitions to rule components of the rule definitions; and rule administrator records, each rule administrator record including a rule administrator identifier; a rule administration program in at least one of the memory devices and operable on the processor to: provide one or more rule administration user interfaces, the rule administration user interfaces operable to receive input to define and modify the rule definitions and the associations of the tag definitions to the rule components; and implementing the limits of tag definitions associated with rule components by limiting how rule components may be modified within the one or more rule administration user interfaces as a function of a rule administrator identifier.
8. A system comprising: a processor; one or more memory devices; a data store held in at least one of the memory devices, the data store comprising: rule definitions, each rule including one or more rule components, each rule component including a reference to one or more values from which an inference is made when the rule is applied; tag definitions which when associated with a rule component limit how the rule component may be modified, the limiting of one or more rule component modifications with the one or more tag definitions including a tag definition specifying a subset of available rule component values from the one or more values defined in the rule definition, the tag definitions each including at least one verb that identifies how the tag modifies data of the available rule component values to form the subset of available rule component values; associations of tag definitions to rule components of the rule definitions; and rule administrator records, each rule administrator record including a rule administrator identifier; a rule administration program in at least one of the memory devices and operable on the processor to: provide one or more rule administration user interfaces, the rule administration user interfaces operable to receive input to define and modify the rule definitions and the associations of the tag definitions to the rule components; and implementing the limits of tag definitions associated with rule components by limiting how rule components may be modified within the one or more rule administration user interfaces as a function of a rule administrator identifier. 9. The system of claim 8 , wherein rule definitions define rules operable within an expert system.