Basically- this is how it works... more of less...
If you don't have "enough rep" or have given "too much rep" recently, you will still get to leave a rep, but it will show as "neutral" regardless of which way you wished to swing the rep points.
I.E. if you have 1 rep point, you might be able to give as much as 1 rep point (pos/neg), but if you gave a rep recently, it may come out as neutral. However, if you have 50 rep points, you might be able to give more rep points each time, and give more rep in general before your rep awards start posting as "neutral".
Like I was trying to explain earlier, this prevents someone who "hates you" from finding all your posts and putting a neg rep on them, and/or signing up extra accounts to give out reputation.
I'm not saying be sparing with the rep awards- if you see something you agree or disagree with, please do click the rep button if you feel strongly enough about it. We really can't get everyone's rep up until everyone starts participating more, regardless of if it hits as a +/-/neutral.
And yeah, David... I've got negative reps on a few. One member went out of his way to dig up a 2-3 month old post he disagreed with to leave me a negative rep.
But- that's what it's there for! If you feel strongly enough about it, drop a rep, whether it's +/-. It's nothing important, and nobody should get bent out of shape if someone gives them a negative rep on something... but once we're really "rolling" with the whole rep thing, it will be an advantage especially to new users.
The reasons why I started this thread in the first place was:
1) There were only 2 users on the forum who had more than "one green block" of rep.
2) Forum users tend to believe that post counts matter, in as much as the legitimacy of the information contained within a user's post.
In the first case, the rep system was mostly useless because nobody really was giving anyone any reps. In the second case, this is tragic, because on so many other forums, I've seen (new users especially) take advice from someone with a high post count and treat it as if it were gospel, not bothering to do any research of their own to confirm or deny the advice, and in some cases they were injured or lost money from following the advice.
As with anything, take anything you read on the internet with a grain of salt and do your own research to back it up.