Have you ever tried to piece together all of the parts that affect what a Tableau Server user can and cannot do?
Have you ever tried to explain it to someone else, other than "It's complicated, complex, confusing, confounding, and mysterious"?
I feel your pain.
After pondering it yet again as I'm trying to figure out how to transfer this arcane knowledge to a client, I finally threw in the towel and sat down to try and map it out.
Here's the result (PDF online).
It's a decent first stab, I think, but I'll be keeping it up as I think of what to add to it, and how.
I'll appreciate any input anyone has, particularly things I've got wrong, followed by things I've missed and suggestions for additional information and presentation improvements.
Until then, happy Permissioning.