You may have heard of the Human Genome Project, but you might be surprised to learn that  there is also a Music Genome Project that uses a panel of experts to associate hundreds of variables with a particular song.  Once you choose a song or artist, similar songs and artists can be identified by matching these variables.  The online showcase for this technology is Pandora.  One of the most fun and effective applications of web 2.0, Pandora is named after the figure in Greek mythology famed for her curiousity (this curiousity ultimately caused us all a bunch of trouble as it resulted in her opening a box that imprisoned all the evils that afflict humanity).  After creating an account, a user can select a  song  or artist, and the software will play similar songs.  You can offer positive or negative feedback on a song to indicate whether you do, or do not,  want similar songs.  You can even create several stations and have the software mix the selections to play a wide variety of music but with most of the songs having qualities that you like based on your indicated preferences.  So go ahead and explore your musical tastes with Pandora. Hopefully, you will not cause as much trouble as the original Pandora!