LTSP is a server-client technology built in order to fulfill the computing needs of small officies and educational environments.
The typical system is a dedicated network in which the server is a powerful elaborator and the clients (known as thin clients) are computers without rotative parts, such as a hard disk, with only a motherboard, a small amount RAM, a very modest CPU, GPU and I/O peripherals (monitor, keyboard and mouse).
The server provides computation power, network connection and a complete operative system, while clients only draw the graphics and handle I/O.
I made a quick and simple presentation of LTSP features, with a stress on how to build a LTSP system easily.
Slides can be downloaded here in PDF format and here in ODP format.