Is there any reason to add a DLL to your /bin directory, but not add a reference to it?

Question

I understand that adding a reference to an assembly from a project makes the namespaces/types/classes of the referenced assembly available to your code. But would there ever be a reason why you'd add an assembly to your /bin, but not need to add a reference to it from your project?

I mean is the DLL all but useless until a reference is added?

Answer 1

Not at all. Reflection allows to load an assembly at runtime without any prior reference. Think how this is useful in a plugin architecture

Answer 2

If you're building ASP Web Site than you just place the dll's in the bin.

if you're creating an ASP Web Application, then you need to add it as a reference.