User-991316286 posted
Precompilation performs essentially the same compilation process that normally occurs when a page is compiled dynamically upon being requested in a browser. The precompiler produces assemblies from the pages, including both the markup and the code. It
also compiles files in the App_Code, App_GlobalResources, App_LocalResources, and App_Themes folders.
http://msdn.microsoft.com/en-us/library/377y0s6t(v=vs.90).aspx