The Song forum is a group of folks sharing, helping and critiquing each others music. And it's peer to peer as apposed to just having your wife critique your latest creation.
I listen to peoples stuff there from time to time when the mood strikes. It's fun, but I don't always have any speakers hooked up.
I have posted some of my songs as well. It's cool to have people listen on other systems and there is a few very keen ears available. I even ended up collaborating on a song when another member took a liking to mine and offered their services.
But why would you want to clutter the main forum with content that is of little interest to your average person coming here for help? When I'm in the mood to listen to songs I go there, I'd hate to have to dig through the main forum for that experience.