To answer the Young Composer rationale, we assume that Young refers to composers that are just getting started and need a place to express themselves.
This site is not intended for experienced composers such as Eric Whitacre, Tarik O'Regan, Don Freund, John Corigliano, Mason Bates, Jennifer Hidgeon. (I could go on for days).
Young implies "young in talent/experience" in the composing field. It's something we have been debating for years now, but we have found no reason to change it. Also, Young Composers is THE largest educationally focused composition website in the world. There are professional composer forums such as ACF and Garritan Forums or whatever that CATER to people with degrees in the field.
But, Young Composers is a way of harnessing the "new" part of the field for some people. When I was 13 or 14, I found YC (that was like 6-7 years ago)! I would have never joined a forum that was intended for adults because I knew I wouldn't fit in. We have many members who have now "grown" up in the community. I am 20, getting my composition degree, and am working hard at becoming a professional. If I were to join a forum now, I wouldn't join YC probably. I understand the idea that it's not meant for my demographic. The people that ARE experienced here are people that joined anyway, have just started composing but they are extremely talented, young 10 and 11 year olds who think they're prodigies (lolz), and just people who are hobbyests.
It's not really meant to be more than that. I think this site is a very focus-driven website, as opposed to a site that is "all-encompassing". There ARE forums that try to be all-encompassing, but they inevitably take on more than they can chew and fail.
IF YoungComposers was to expand and grow, then this would be the website to change because we have so many active people now.
This was not the case when the website first opened. I am not sure if it is the time for anymore change, though. YC has undergone extreme plastic surgery and therapy to get where it is right now, moderately successful in a newer technological milieu. I'm afraid of pushing the envelope, myself.