Programs that accomplish simple tasks, developed in the simplest way, reduced programming, testing and debugging time, and very easy to modify by anyone with little skills.
Those using very little technological stuff (...), with the main focus being the KeepItSimpleSam aproach. Besides being simple, these programs do what they were intended to do, the way that it was intended. (was that clear?)
Sometimes used to test (or show the way to implement) new technologies or complex algorithms.