An actor's reel showcases the actor's performances, cut together to give the viewer a clear idea of the actor's range and skill. Actor's reels are usually tailored to reflects the type of work they're seeking, i.e. a reel for commerical work, on-stage work, film work.
Actor's reels are especially useful for promoting on-camera work as they give directors and casting agents an idea of the actor's on-camera presence.
External Links Edit
Interview with Actor Rusty Schwimmer (podcast)