  This paper reviews the rich corpus of observational evidence for tidal
effects in short-period binaries. We review the evidence for ellipsoidal
variability and for the observational manifestation of apsidal motion in
eclipsing binaries. Among the long-term effects, circularization was studied
the most, and a transition period between circular and eccentric orbits has
been derived for eight coeval samples of binaries. As binaries are supposed to
reach synchronization before circularization, one can expect finding eccentric
binaries in pseudo-synchronization state, the evidence for which is reviewed.
The paper reviews the Rossiter-McLaughlin effect and its potential to study
spin-orbit alignment. We discuss the tidal interaction in close binaries that
are orbited by a third distant companion, and review the effect of pumping the
binary eccentricity by the third star. We then discuss the idea that the tidal
interaction induced by the eccentricity modulation can shrink the binary
separation.
  The paper discusses the extrasolar planets and the observational evidence for
tidal interaction with their parent stars which can induce radial drift of
short-period planets and circularization of planetary orbits. The paper reviews
the revolution of the study of binaries that is currently taking place, driven
by large-scaled photometric surveys that are detecting many thousands of new
binaries and tens of extrasolar planets. In particular, we review several
studies that have been used already thousands of lightcurves of eclipsing
binaries to study tidal circularization of early-type stars in the LMC.
