何时以及为什么要实现IComponent，IContainer和ISite？

I've wondered for a long time what IComponent, IContainer, and ISite are for. I've read the documentation, but it is extremely vague (or I'm thinking about it too hard). I know that if I create a class as a component, it can be used in the Visual Studio designer. But I'd really like to know more generally: what does the Component/Container pattern accomplish, and can it make my life easier?I've wondered for a long time what IComponent,