There are some missions that you can do over and over every day. You make good credits and receive daily commendations for doing these missions. The commendations will allow you to purchase high level implants, gear, speeders and mods. Daily heroics also give you commendations, credits and mods as a reward. Dailies are largely level 50 missions on Ilum, Belsavis, and Corellia. Still there are other daily missions too, space missions, PvP and others.
So simple answer Dailies can me any mission that is repeatable, but only once a day. Just usually when someone says they are doing Dailies, they are about to do the level 50 dailies on Ilum, Belsavis or Corellia.
Last edited by mimartin; 04-17-2012 at 12:08 PM.