New users are green, iirc 50 or 100 karma points required to get normal grey

Feels like they are more superior than us based on his color.

In English being "green" can mean being "new," like a sapling or new shoots on a plant, which are often bright green.

I don't know for sure if that's why they chose to make new users green but that's how I view it.

That's probably a cultural thing. In some cultures, red is superior to green.

Really, it's not about them being better or worse than a user with more Karna. It's just a signal to everyone that this person might be advertising or AstroTurfing.

What?! I didn't know it indicates that the user is "untrusted", I'm from Sweden and my impression has been that the green users are super users of some kind.

That was my impression as well. I never knew that. Guess it's good to know though.