Systems and methods for storing and retrieving goods and services information using parameter/value databases

A method of storing descriptors of marketplace items for possible sale or purchase, comprising:

• providing a database having parameters associated with classifications;
• providing, via a computer system comprising at least one computer, a first parameter interface that accepts a classification for an existing classification in the database and a new parameter, wherein the new parameter did not exist in the database prior to receipt;
• designating the new parameter as a recommended parameter for the classification upon determining that the new parameter is used by a user of the computer system with the classification;
• providing, via the computer system, a second parameter interface to receive the classification as a selected classification and to display a list of database parameters associated with the selected classification comprising a recommended subset of the database parameters associated with the selected classification, wherein the recommended subset comprises the new recommended parameter, and wherein the recommended subset of the database parameters are distinguished from a non-recommended subset of the database parameters.