1. An automated method of conditionally propagating metadata among documents comprising: defining a plurality of groups of metadata instances; assigning a plurality of propagation coefficients to each said group, where each said propagation coefficient assigned to each said group is associated with at least one document attribute and is based upon correlating said associated document attribute with determinations of document-to-document propagations of said metadata instances of said group; selecting first and second documents between which a specific metadata instance may be propagated; and basing metadata propagation from said second document to said first document upon a plurality of said document attributes, including (a) determining a particular said group in which said specific metadata instance resides; (b) for each of said document attributes upon which said metadata propagation is based, identifying said associated propagation coefficient that was assigned to said particular group; and (c) for each of said document attributes upon which said metadata propagation is based, comparing said first and second documents with respect to said document attributes.