Independent of stellar modelling, global seismic parameters of red giants provide unique information on the individual stellar properties as well as on stellar evolution. They allow us to measure key stellar parameters, such as the stellar mass and radius, or to derive the distance of field stars. Furthermore, oscillations with a mixed character directly probe the physical conditions in the stellar core. Here, we explain how very precise seismic indices are obtained, and how they can be used for monitoring stellar evolution and performing Galactic archeology.