Since May 2003, when Apple Computer's online music service iTunes opened its digital doors, the drums announcing other online music services--new enterprises as well as existing music services spruced up and recharged--have been steadily beating.
Online music’s winners and losers | CNET News.com
I have still to try an Online Music Service, but then again, I only listen to underground live mixes which I haven’t been able to find legally for sale anywhere online.