What is a scene, and what use is having more than one scene in a .blend?
I’ve used Blender for quite a while and so far haven’t had any use for multiple scenes in one file. That might be because I’m used to other 3D software and they don’t have a feature like that, so I just don’t think about it.
Here’s the wiki page about it:
http://wiki.blender.org/index.php/Doc:Manual/Interface/Scenes
What I use Scenes for are containers for importing. Say you have a complex model you want to import, but you are not sure how you are going to integrate it into your working scene. Simply import the entire scene into its own scene space and then you can pick and chose which parts you want to link into your original scene. After you have made your decision, you can simply delete the entire imported scene. Anything you have cross linked will remain, while the rest will be removed after a save and re-open.
I believe scenes might have more uses by the game engine. For example, one scene might be the game level menu selection, another scene might hold characters, then another scene may be the runtime environment.