Web Application

Web Application  is an application which is stored on the web server and delivered over the www or internet. Web Application is vary popular and the reason of it's popularity is ubiquity of the web browser as a client. Examples of web browsers are Internet Explorer, and Mozilla Firefox.
It has ability to update and maintain web application without distributing and installing software on potentially thousand of computer.
Web applications are used to implement webmail, online retail sales, online auctions, wikis, discussion boards, weblogs, and perform many other functions.