Why the name? What does OBTINEO mean?

I have, occupy, possess, hold.
I preserve, keep, maintain, uphold, persist in.
I assert, show, prove, demonstrate, maintain.
I gain, acquire, obtain, achieve, win.
I maintain myself, prevail, last, stand, continue, succeed.

Do I have to place my port directly in front of me?
Why are there no purple resources?
Why so few resource cards/troops?
Why isn't the trading of Resource Cards and POW's allowed?
What does each resource represent?