A "web site" has its code in a special App_Code directory and it's compiled into several DLLs at runtime. A "web application" is precompiled into one single DLL that is built and copied in the Bin directory.

A web site is just a group of all files in a folder and sub folders. There is no project file. All files under the specific folder - including your word documents, text files, images etc are part of the web site.

You have to deploy all files including source files (unless you pre compile them) to the server. Files are compiled dynamically during run time.

In website since there is no project file, there is nothing that you can double click to open the web site in Visual Studio for editing. You have to open Visual Studio first and then open the site from Visual Studio