You can't redistribute the shader, but you are entirely free to share presets that call it. You have to remember that this is a true shader, written in RSL code and compiled, not settings for Shader Mixer where you can make changes by relinking the bricks. The nearest Poser equivalent would be a Python interface that made changes to the nodes and which you could save settings for: you could share the settings, but not the Python script or the underlying nodes (but in the DS case there are no nodes - it's just a analogy).