14. A system, comprising: one or more processors; and a memory comprising program instructions executable by the one or more processors to: receive a request to generate a new playlist; and in response to receiving the request: determine an initial ordered sequence of one or more audio files; and generate a new playlist comprising an ordered sequence including an indication of one or more of the audio files from a playlist database, wherein said generating a new playlist comprises applying the initial ordered sequence to an N-gram statistical model of the playlist database; wherein the playlist database comprises a plurality of audio file playlists, wherein each audio file playlist indicates an ordered sequence of audio files; and wherein the N-gram statistical model models ordering sequences of the audio files indicated in the playlists.
14. A system, comprising: one or more processors; and a memory comprising program instructions executable by the one or more processors to: receive a request to generate a new playlist; and in response to receiving the request: determine an initial ordered sequence of one or more audio files; and generate a new playlist comprising an ordered sequence including an indication of one or more of the audio files from a playlist database, wherein said generating a new playlist comprises applying the initial ordered sequence to an N-gram statistical model of the playlist database; wherein the playlist database comprises a plurality of audio file playlists, wherein each audio file playlist indicates an ordered sequence of audio files; and wherein the N-gram statistical model models ordering sequences of the audio files indicated in the playlists. 18. The system as recited in claim 14 , wherein, to generate a new playlist, the program instructions are further executable by the processor to, if there is insufficient coverage in the N-gram statistical model for the initial ordered sequence of one or more audio files, apply the initial ordered sequence to a lower-level N-gram statistical model of the playlist database.