I came across this site about a week ago during my study bender and kind of forgot about it until now. Essentially, Musicplasma takes the name of an artist that you punch in and spits out a graph that contains all those artists who are related in some way (genre, epoch, etc) to the artist you're querying — a visual search engine. You can move around the graph and click on the other artists to start the search anew or you can zoom in and out of the artist currently in focus.
The closer the artists are, musically speaking, the closer to each other they will be displayed on screen, you will be likely to appreciate artists close to the one you selected first.
I've put it through quite a few tests and it seems to be fairly on point, but you can definitely break it (e.g., "the streets" produces some whack results). Either way, it's really fun to play around with and for those of you who who pay for music, it provides a list of the artist's albums and links to them on Amazon.