An article I submitted to the SCBWI (The Society of Children's Book Writers & Illustrators) Bulletin last year appears in the current issue: January/February 2009. The article's about defining young adult fiction (and what an immensely difficult task that is!) and ponders that YA books may be missing out on potential readers because of where they're situated within bookstores.
Who exactly are those teen fiction books for readers fourteen and up intended for if, as common wisdom has it, readers over the age of fourteen have moved on to the general fiction section? Hmm.
You can take a look at the original article "What Is YA and Where Should We Put It" on the SCBWI site (or a hardcopy of The Bulletin) if you have an SCBWI membership. There's also a reworked/updated version from October right here.