The reason for suggesting no tiers is based on experience. You have a relatively small core of regular posters and I bet, a lot of people like me read far more than they comment, or actively participate. Creating a system of elite and peasants would be divisive as it is in real life. I know of a large racing forum that had a "secret" board for their pets. The door got left open one time and many hurtful comments were exposed and the forum never recovered. Not saying anything remotely similar is possible with the great people I've interacted with here, but why create the opportunity?

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