Smart client

Smart Client is a term describing an application environment which:

• delivers applications over a web http connection
• does not require installation (or provide automated installation and updates)
• automatically updates without user action
• has the look and feel of desktop applications

The Smart Client approach came about because when businesses tried to develop web application to replace their old desktop applications, user productivity decreased. This was because web-based user interfaces based on server-side HTML generation are typically not as responsive, have fewer hot keys and require more use of the mouse, etc.

Smart Client applications bridge the gap between web applications and desktop applications. They provide the benefits of a web application (such as leveraging the internet and offering remote access to data) while still providing the snappy look and feel inherent to desktop applications.

Mainly there are four platforms for building Smart client applications :
Flex : from Adobe.
JavaFX : from SUN.
WPF : for Microsoft
DataSnap/WebServices : from CodeGear.