There is increasing evidence from variability studies, line profile analyses, and the theory of radiation driven winds, that stellar winds are highly structured. Spectral analyses that ignore these inhomogeneities will lead to erroneous results.

Inhomogeneities can be categorized into 3 types: density inhomogeneities, velocity inhomogeneities (i.e., non-monotonic velocity laws), and temperature inhomogeneities. Each of these gives rise to distinct effects on the observed spectrum. For example, density inhomogeneities affect the strength of electron scattering wings, velocity structure most noticeably affects the blue absorption components of P Cygni lines, while high temperature zones in an otherwise cool wind give rise to X-rays.

Unfortunately the computational techniques and computational power required to handle a realistic structured wind (even if imposed and not solved for self-consistently) do not yet exist. We examine recent progress in the investigation of the influence of structured winds, and discuss what can be done in the near future.