Lately, I have been using the Genius feature of iTunes to make playlists, especially when I'm in the car, and I must report to you, the people, that the experience lives up to the name, or almost. In case you don't know, the way it works is, you pick a song, which starts playing. You hit the middle button, and the menu asks if you want to add it to an On-the-Go playlist, or if you want to turn on Genius. You select the "turn on Genius" option (by all means!), and it creates a playlist of twenty-five songs that connect with the one with which you started.
On the way up to and back from Idaho, the historian and I used Genius to rather stunning effect. The first one we started with was a Thelonious Monk tune, and from that we got Charlie Parker, Ornette Coleman, Brad Mehldau, Wes Montgomery, and on and on. A very satisfying jazz list. I created a great retro experience by starting with Little Feat, "Willin'," and coming up with all sorts of seventies folk-ish stuff. Deeeelightful.
The best by far occurred when we started with Willie Nelson, "Whiskey River," which gave us (of course) Johnny Cash, June Carter Cash, Kris Kristofferson, Steve Earle, Gillian Welch . . . it's like when you get on a good run of shuffled tunes, but more coherent: lots of surprises and so much enjoyment. If you are an obsessive like me and have more tunes than you know what to do with, I think you might enjoy Genius as a different way of accessing your music.
I will say that when I started with a Ben Folds tune, I got a lot more Ben Folds, which leads me to conclude that sometimes, Genius just doesn't have the energy. Like the rest of us.