Inversion of Control - Dependency Inversion Principle - Castle's Windsor/MicroKernel

First, is the Dependency-Inversion Principle. Rather than the application being dependent on the blog services and the blog services dependent on the database, we have inverted the relationship. The details are no longer in control of the application. The database is dependent on the blog services and the blog services is dependent on the application, allowing us to plug-in various databases and blog services at will without touching the application.

http://codebetter.com/blogs/david.hayden/archive/2006/10/13/Inversion-of-Control-_2D00_-Dependency-Inversion-Principle-_2D00_-Castle_2700_s-Windsor_2F00_MicroKernel.aspx