  I briefly review the current state of the modelling of photospheric activity
based on the high-precision optical light curves obtained with MOST, CoRoT, and
Kepler. These models can be used to search for active longitudes where activity
is preferentially concentrated, estimate the amplitude of stellar differential
rotation, and look for short-term activity cycles as, e.g., in the case of
CoRoT-2. In the case of a late-type star accompanied by a transiting hot
Jupiter, the small light modulations observed during transits when a dark spot
is occulted by the disc of the planet are also briefly considered. They can be
used to derive information on individual active regions as well as on stellar
rotation and the spin-orbit alignment of the system.
