Here's one...
Thou shall be respectful and kind to other forum members when they mistakenly post something in the wrong forum or "violate" these unwritten rules. Rather than talk down to them, suggest the forum that would be more accurate. Suggest respectfully when a post might not have enough information, or "violates" what you might think is a unwritten rule. We all started out somewhere and probably had the same questions we might think is obvious now. Shaming someone because they don't know does nothing for this forum.
The hobby is small enough without having potential, new, and old members alike not being able to enjoy themselves here and find the information and help they're looking for. All this does is drive folks away. Not everyone is internet savvy.
RESPECT. Goes a long way to making this forum great.
