Thanks for your comments. I do agree with all your points: shuffle and repeat will come soon, and I do need to set up a FAQ.
About iTunes DJ: no need to have iTunes open. It doesn't sync with your iTunes' iTunes DJ, it's just a place to queue the songs you wanna hear later. It does start empty, and every visitor has its own separate iTunesDJ.
You can queue songs there to be played later, by right-clicking on a song on any playlist, and selecting "Add to iTunesDJ". If you select "Play next in iTunesDJ", it will be added to the list, and will start playing.