Measurements by our group (and others) of the thermoelectric power in the normal state of cuprate superconductors show that thermopower, like the resistivity and Hall angle, shows a systematic pattern intimately related to the superconductivity. In the strongly overdoped regime, the transport properties show relatively conventional metallic behavior: for example, thermopower is often approximately proportional to temperature. As the hole concentration is then decreased and Tc increases to its maximum value, the in- plane thermopower shows an approximately temperature-indecent shift upwards to positive values, retaining a similar temperature coefficient of around -0.03 (mu) V/K2 for a wide range of cuprates. This continuity in the transition from more conventional behavior is easier to explain in the Van Hove scenario and by electron-phonon effects than by some exotic mechanisms for the origin of cuprate superconductivity. We also note that thermopower patterns surprisingly similar to that in the cuprates are seen in non-cuprate superconductors such as NbN, and also in the nonmagnetic cubic perovskite superconductor Ba1-xKxBiO3 (which, however, shows a nonlinearity at around 150 K). The thermopower of fullerene, Chevrel-phase compounds, NbN and disordered metal superconductors shows a low-temperature change of slope in good agreement with electron-phonon renormalization, demonstrating that thermopower can in many cases be used as a probe of the electron-phonon interaction.