I believe this is one of the least featured feature of the HTC One. Do you know you can actually play your song and at the same time display the lyrics of the song (most of them) in a Karaoke-like manner?
Actually, what it does is that it access the GraceNote Media Database for the Album Artwork and Lyrics. Once it has it, it will display the lyrics along with the song. Very nice feature (although it might not work sometimes). Check out this video (BTW, I bought those songs and turned them into MP3).
Here is a screenshot of the menu you can find when you use the Music Player.
Notice that it also has SoundHound integrated into it? When you click on it, it will activate the app to search for the information of the song or music.