Examples of recent investigations in several laboratories, where measurement of effects due to electron spin polarization provided new insight into surface phenomena, will be reviewed. The results to be discussed include the use of spin dependent electron scattering to determine the surface potential barrier, the magnetic critical behavior of a semi-infinite solid, and the low temperature surface magnetization. Examples from spin-polarized photoemission include studies of the nature of the resonant 6 eV satellite in Ni and of oxygen-induced magnetism in a Cr(100) surface. The use of angle-resolved spin-polarized inverse photoelectron spectroscopy to obtain information on spin dependent band structure of unoccupied states will also be described. The rapid growth of measurements involving electron spin polarization, where previously only electron energy or momentum was measured, is explained by the development of new experimental techniques like the GaAs spin-polarized electron source and advances in spin polarization detectors.