What are fat clients, thin clients and rich media?

These terms define the essential functions of an end user’s computer, a “client” when it’s connected to a server via local or wide area network-most commonly a client-server systems.

Fat Client-a host computer that runs applications locally using its own resources (its Operating System, plus installed software applications, and storage/memory), but connects to server for retrieving/storing ancillary data (such as when downloading web pages using a browser application, or retrieving email from an email server). The application is hosted and functions locally on that end terminal (client).

Thin Client: Any client computer that enables functions normally reserved for Fat Clients, to be handled remotely on a server. The latest generation of smartphone/PDAs are now beginning to utilize this functionality, but basically running applications remotely from a server (beyond data retrieval). Ajax programming in web 2.0 apps, for example, allow the server to do the processing to enhance the functionality of the enhanced web site. Fluther uses this to periodically update the data and status of a thread in real time.

While many debate the future of client-based computing, we are already seeing signs that server-based functionality is increasing; beyond remote storage (think .mac and iDrive, google), and the concept of broadband over wireless is a major factor in supporting this emerging construct for mobile computing. Ultimately a thin client would run apps remotely using powerful remote server clusters, but retrieve data from them in real time as if it were doing the computing itself.

Rich media: a general terminology for interactive multimedia on the web; the term expands the notion that audio, video, text has an interactive component that allows the user to interact with it in some capacity; a basic example can be to embed a hyperlink in an image file or video, whereby clicking redirects a browser to a website.

My terminologies are limited, but for more you can wiki those terms and get more detailed explanations.