The importance of the dependence upon Bjorken-x of the cross section for deep-inelastic ep diffraction is emphasized. It is suggested that an accurate measurement of a comparison of the Bjorken-x dependence of this cross section with that of the totally inclusive ep cross section may be the best way of determining the properties of the pomeron and whether they are universal and thus consistent with factorization. Results of such a comparison in the form of a measurement of the ratio of the deep-inelastic diffractive and total cross sections are reviewed and discussed. The x dependence of the measure of the total contribution of diffraction to deep-inelastic scattering is also presented and its significance stated.