Hi all, I'd like to introduce Chordify http://chordify.net/ [1], an online music player that extracts chords from musical sources like Soundcloud, Youtube or your own files, and shows you which chord to play when. Here's an example song: http://chordify.net/chords/passenger-let-her-go-official-video-passengermusi... The aim of Chordify is to make state-of-the-art music technology accessible to a broader audience. Behind the scenes, Chordify uses the HarmTrace Haskell package to compute chords from audio. I've been working on this project with a couple of colleagues for a while now, and recently we have made the website public, free to use for everyone. We do not use Haskell for any of the frontend/user interface, but the backend is entirely written in Haskell (and it uses pretty advanced features, such as GADTs and type families [3]). We're particularly interested in user feedback at this stage, so if you're interested in music and could use an automatic chord transcription service, please try Chordify! Cheers, Pedro [1] http://chordify.net/ [2] http://hackage.haskell.org/package/HarmTrace [3] José Pedro Magalhães and W. Bas de Haas. Functional Modelling of Musical Harmony: an Experience Report. In Proceedings of the 16th ACM SIGPLAN International Conference on Functional Programming (ICFP'11), pp. 156–162, ACM, 2011. http://dreixel.net/research/pdf/fmmh.pdf