There are many musicians around that utilize working with loops.  The basic principle of looping is to record sound in real time (that is, not from pre-recorded samples) onto a certain medium in a looping device.  The looping device then plays the sound again, once or more time.  The time of the sample may be short (if shorter than one second we might be talking about delay effect) or longer, even several minutes.  Looping can be used in various styles of music, especially in various experimental projects, in creating sound collages, etc.  This wide variety of looping implies that when a musician talks about his work with loops, it does not say anything yet about his or her musical style.

For more about looping visit some of the following websites:

Looper's Delight.