It provides extra information by which it makes the site easier to manage. It can include text files using the #include statement, retrieve the size and last modification date of a file, defines how variables and error messages are displayed and inserts the values of HTTP variables in the page sent back to the browser. 

• ASP executes code on the server side whereas the browser interprets HTML. • ASP can use any scripting languages • Gets feedback from the user and return information to the user • Create pages that will be customized to display only things that will be of interest to a particular user • Can edit contents of a web page by updating a text file or a database rather than the HTML code itself

Virtual directories are aliases for directory paths on the server. It allows moving files on the disk between different folders, drives or even servers without changing the structure of web pages. It avoids typing an extremely long URL each time to access an ASP page.