Applications of optical polarimetry are reviewed, and limitations of polarimetry are discussed in the context of information content and error management of polarimetry applications. Polarimetric measurement techniques are categorized as spectral or nonspectral, active or passive, monostatic or bistatic, and whether or not measurements of the complete Stokes vector or Mueller matrix are made. Specific examples from the literature of passive polarimetry, laser polarimetry, and spectropolarimetry are discussed.