What is the difference between "typename" and "class" template parameters?

For templates I have seen both declarations:

template < typename T >
template < class T >

What's the difference?

And what exactly do those keywords mean in the following example (taken from the German Wikipedia article about templates)?

template < template < typename, typename > class Container, typename Type >
class Example
{
     Container< Type, std::allocator < Type > > baz;
};