Found a bug/easter egg: If you zoom all the way out and center Elton John at the top of your screen, then zoom in to the middle zoom level, you can see a map for TV shows as well.

http://img16.imageshack.us/img16/2796/tvmap.png

Looks awesome. Seems to be sourced from Last.fm.

Also, don't miss:

map of movies: http://www2.research.att.com/~yifanhu/MovieMap/index.html

map of tv: http://www2.research.att.com/~yifanhu/TVMap/index.html

and map of books: http://www2.research.att.com/~yifanhu/BookMap/index.html

any idea how the relationships are inferred?

[i've used last fm's artist tags to construct relationships between artists (artists with tags in common are related) and so generate playlists that of related tracks - the last fm api is really easy to use.]

The Blues Brothers are between Frank Sinatra and The Beatles?