As I understand it, it's like this:

Blue icon - User Yellow icon - GA user Purple icon - Moderator Red icon - Admin

But there are also green icons and other colors?

Blue: Regular User Gold: Gold Account User Purple: Mini-Mod Red: Staff Member Green: NPC Account Gray: Keith

Which can be found on the FAQ: https://subeta.net/help/faq.php#Forums

If you are interested, are 16 or older, and live in the United States, you can apply at that time.

Uhh, what? That's literally discrimination. I don't live in the US, so I can't become staff if I apply?

currently, their system is set up only to be able to pay u.s. citizens. because staff above mini-mods are paid real usd. and i don't see their system changing anytime soon because staff above mini-mods have not changed except with becoming the public rep last year. before that, staff were stagnant and none of them are looking to give up their jobs anytime soon.

i'm sure down the road, more applications will open, but it's unlikely in the foreseeable future.

Is there a way to specify that I give up my right to be paid? Some people might just want to volunteer...

not that i'm aware of. however, there are no applications open at this time and they rarely open applications for paid staff, even mini-mods are quite set now. also, staff are usually chosen between members of the site that are deeply active in the community.

[edit]

you also seemed to have missed this tidbit, anyway; "The age and location restrictions are due to legal and tax issues. User Administrators, our regular staff moderators, are usually hired from the pool of Minimods. "