I listen to lots of electronic music, and I'm a professional DJ.
Electronic music is a very diverse and complex music category, and have lots of genres and sub-genres. Electronic music producers usually try to transpose genre boundaries, and they usually produce songs contained in two or more equally important genres. For instance, a track can be contained in the genres "house" and "techno", or "disco", "techno" and "acid".
Also, it's really very common that electronic music artists collaborate with each other. Songs produced in collaboration do not belong to one single artist, but to two or more. In this case, it's not correct to say that one is the main artist, and the others are second artists (collaborators, composers remixes, or whatever) - they all detain the same equal authorship status over the composed track.
The problem with iTunes is that it supports one single genre, and one single artist per song. Sure, there's the album artist, but, again, that doesn't apply to albums where multiple artists participate with equal importance. And using "V.A." or "Various Artists" in the song artist or album artist fields is ugly and useless - it doesn't say anything relevant.
I know that Smart Playlists and Grouping features can help alleviate this deficiency, but they don't solve them at all. They're not elegant and complete solutions. If you browse the iTunes library, you will still see tracks as having only one genre and one artist, which is very frustrating.
What I ask is really easy to implement. In fact, it wouldn't require to alter the existing ID3 and tag scheme. Just split artists and genres using a colon or semicolon character. For instance, in the "Artist" tag, iTunes can store the following:
"Christian Smith; Mark Broom; Renato Cohen"
and then, in the browser, iTunes could display "Christian Smith", "Mark Broom" and "Renato Cohen" as three distinct artists.
The same could be used for the "Genre" tag:
"Techno; House; Progressive"
could be see, in the browser, as three different genres: "Techno", "House" and "Progressive".
I've made an extensive web research, and I know that this deficiency doesn't annoy only me, but lots of other users. And it's a pretty old request too - dated from 2003.
Please, Apple, implement this feature. My huge electronic music collection really needs to be categorized into multiple artists and multiple genres.