On minute, you think you have a perfectly normal VS 2005 Web Application project.  The next it's a website.  What's going on?

I've just been through it so I'll, hopefully, spare you some pain.  Remember when I was moving projects around to deal with hard coded paths in VS 2005 solution files with VB.NET?  I had moved around the *.vbproj.webinfo file too.  Apparently that one little file is all that holds together the fragile world of web application projects.  Move it and they revert back to their more primal version; the website.  It looks like that's the case with *.csproj.webinfo though I haven't had the pleasure of experiencing that first hand.

It's a tiny little file with the location of your Web Application in it, that's it.  It shouldn't be in source control, though keeping all development machines looking the same does help, so I'll deal with that. 

Can anyone tell me what's so special about that one file?