What is an empty interface used for

Question

I am looking at nServiceBus and came over this interface

namespace NServiceBus
{
    public interface IMessage
    {
    }
}

What is the us

Answer 1

In java Serializable is the perfect example for this. It defines no methods but every class that "implements" it has to make sure, that it is really serializable and holds no reference to things that cannot be serialized, like database connections, open files etc.