Popularly , they are used in clean tone to play easy slow stuff like the intro from "Don't Cry" by GNR or most clean stuff in Scorpions songs... And these are usualy the same shape and pattern of regular chords , but you pick notes individualy in a certain sequence.
Or probably you have read the term arpeggio accompanied by sweep picking , which is a somehow advanced technique , used to shred over arpeggios ... Sweeping arpeggios have a little bit different patterns & fingering than regular chords , to make them easier to play fast ... I can post you some if you'd like.
[Edited by SLY on 09-19-2003 at 10:21 AM]