Using the Compilation Tag to Reduce the Number of Artists
Now and again you'll get an album by a principal artist, but with one or two tracks by other artists. It's not strictly a compilation, because these secondary artists aren't contributing many songs.
The problem became most apparent when producing HTML catalogs using iTunes Catalog. These secondary artists add unnecessarily to the total artist count and appear at random throughout the catalog.
Case in point: The Rolling Stones' Still Life. This album begins with a track by Duke Ellington and is ended by Jimi Hendrix. It's quite clearly a Stones album, but you can't tag the above two tracks with the Stones as the artist.
Solution: If you select the secondary artists' tracks and get info, then set the Compilation tag to "Yes", they will disappear into the Compilations folder in your Music folder. In this case, the album is still in the Rolling Stones folder, and in iTunes Catalog, the other two tracks become listed under the album name, not the individual artists.