Actually there is no magic involved, it relies on music metadata found in music files tags and external information providers such as last.fm. Then to use MPD_sima (or any advanced music players, MPD among them), you need to ensure your library is correctly tagged (see Music library metadata convention).
- To queue tracks from similar artists:
start playing a track in MPD
# runs against localhost MPD (or whatever is set in MPD_HOST/MPD_PORT) mpd-sima # runs against a specific MPD server mpd-sima --host mpd.example.org
These manual pages were written for the Debian system (and may be used by others).