IOC (inversion of control) is a key strategy for reducing coupling.
The easiest way to understand inversion of control is to see it in action.
NK: inversion of control is a mindset, and dependency injection of any kind (with or without a framework) relies on your software being designed with the goals of inversion of control in mind.
Writing your software with inversion of control in mind also makes unit testing much, much easier, because you can swap out real implementations for mocks in your tests.
