1. A computer system comprising: a repository having stored therein predefined data elements configured for use by a sender system in identifying information portions in electronic communications such that the information portions are automatically displayed and used by a receiver system to interpret contents of the electronic communications, each of the predefined data elements being associated with semantic information indicating its definition and intended use, the receiver system using the semantic information to display and interpret the electronic communications, wherein the data elements identify corresponding ones of the information portions according to the semantic information; and a modeling tool that, upon selection by a user, displays any of the predefined data elements for editing of the predefined data element and not of the information portions, the modeling tool presenting the semantic information for the selected data element, wherein an edited predefined data element is stored in the repository and accessed there by the receiver system.