From their website:
SystemImager is software that makes the installation of Linux to masses of similar machines relatively easy. It makes software distribution, configuration, and operating system updates easy, and can also be used for content distribution.
SystemImager makes it easy to do automated installs (clones), software distribution, content or data distribution, configuration changes, and operating system updates to your network of Linux machines. You can even update from one Linux release version to another!
It can also be used to ensure safe production deployments. By saving your current production image before updating to your new production image, you have a highly reliable contingency mechanism. If the new production enviroment is found to be flawed, simply roll-back to the last production image with a simple update command!
Some typical environments include: Internet server farms, database server farms, high performance clusters, computer labs, and corporate desktop environments.