  We discuss the observational phenomenology of Seyferts from the point of view
of the disk model, and argue that the spectral variability may be related to
geometrical changes of the cold matter which provides a source of seed photons
for Comptonization in a hot central disk. One possible configuration is a model
with quasi-spherical accretion in the central part of the disk, with
variability determined by the dynamics of the transition zone between the cold
and hot disk. The soft excess component appears as a driver of spectral
variability and contributes significantly to the source energetics.
