From some discussion earlier today, you must have a collective score of 500 upvotes before you have the ability to downvote. I would guess that is to enforce a period where new accounts can get used to the generally accepted standards for discussion here.

Thanks. I had 7 but now I have 5... lol

It means you're "green", in the sense of young or inexperienced - i.e. a relatively new account.

Huh. Cool. I just kind of figured I'd stumble across an answer to that one and here I am. Makes good sense too. Thanks.

Hey, here's a question, why does the comment reply link sometimes not render until I refresh the page? Are they on a timer or something?

Yes, if a thread is gaining posts too quickly, HN will suppress reply buttons to try and prevent people from making hasty/not well thought out posts.