Photoemission into an electrolyte is discussed with special reference to the possibility of investigating photoelectron excitation mechanisms. Recent experimental studies are described and the use of polarized light and of single crystal surfaces is emphasized. The anisotropy of bulk photoemission is outlined and the experimental results on gold and copper single-crystal surfaces are discussed within this model. A deterioration of anisotropy effects is seen to occur on rough and adsorbate-covered surface due to a non-specular electron scattering. In the study of silver surfaces the optical excitation of plasma oscillations is found to manifest itself strongly in the photoelectron current