​Last.fm is a song dataset that contains the largest song-level labels and pre-computed song-level similarity studies. All data is associated with the MSD song and can be linked to other MSD resources: audio characteristics, artist data, lyrics, etc. The data contains 584,897 tracks, 522,366 unique tags, 8,598,630 track-tag pairs, and 56,506,688 track-similar track pairs. This dataset was released by MSD in 2011.