What's the difference between ContentControl and ContentPresenter?

ContentControl is a base class for controls that contain other elements and have a Content-property (for example, Button).

ContentPresenter is used inside control templates to display content.

ContentControl, when used directly (it's supposed to be used as a base class), has a control template that uses ContentPresenter to display it's content.

My rules of thumb (not applicable in every case, use your judgment):

1. Inside ControlTemplate use ContentPresenter
2. Outside of ControlTemplate (including DataTemplate and outside templates) try not to use any of them, if you need to, you must prefer ContentPresenter
3. Subclass ContentControl if you are creating a custom "lookless" control that host content and you can't get the same result by changing an existing control's template (that should be extremely rare).

ContentPresenter is usually used in a ControlTemplate, as a placeholder to say "put the actual content here".

A ContentControl can be used anywhere, not necessarily in a template. It will pick up any DataTemplate defined for the type of content assigned to it

I recently wrote a post on my blog regarding these two controls:

ContentPresenter vs ContentControl

The ContentPresenter.ContentSource is what actually makes the biggest difference between the two classes. ContentSource property makes sense only within a ControlTemplate; it determines which TemplatedParent property the content should be mapped with. For example, if a control contains a dependency property MyProperty1, then we might find the following within its ControlTemplate:

<ControlTemplate TargetType="MyControl" >
    [...]
       <ContentPresenter ContentSource="MyProperty1" />
    [...]
</ControlTemplate>

The content of the ContentPresenter will receive the value of MyProperty1.

Please note that if the name of the property is Content, there is no need to specify ContentSource as it is the default value.

For those who know angularJs: this is similar to transclude mecanism.