Many of the exoplanets discovered so far are close to their stars and therefore, like our planet Mercury, will have their rotations and orbits locked together by the tidal forces on them. (Mercury rotates three times for every two orbits around the sun. ) In this video, Tony Dobrovolskis of NASA Ames and the SETI Institute discusses how such orbital/rotation synchronization will affect the conditions on the planets and what it could mean for seeing the planets directly:

Exoplanets discovered to date show a wide range of orbital eccentricities; the angles between their spin equators and orbital planes are still quite unknown, but these “obliquities” may range widely as well. Both eccentricity and obliquity can have profound effects on a planet’s seasons, as well as on its cycle of night and day. Remarkable patterns of insolation occur on synchronously-rotating planets, and on those in other spin-orbit states, with implications for their climates, detectability, and habitability.

http://www.youtube.com/watch?v=8_XQ_wSmg2s&feature=share