Shutterfly details

I've searched the Gallery Wiki, FAQ and these forums, but haven't been able to find much information on Shutterfly.

When customers order prints, do I earn a commission, or does Shutterfly earn everything, and I nothing?

If I am able to earn via Shutterfly referals, can I adjust prices or commissions?

Again, if I earn money via the Shutterfly plugin, how can I track amounts earnt, and how is payment made?

(Warning: There will be more questions once I've got some answers)

Thanks, in advance, for your help