Yesterday, there was some discussion of posting guidelines here at Amiga.org, and now you are re-designing Amibench, though AmiBench is not a discussion site, presumably one thing you will still need is well laid out guidelines for posting an add, or even an auction.
So, because this line of thinking is of interest to me, that is where I will make my comments.
Wayne's guidelines, in additions to the terms of use you already outline.... are a good starting point...but you can make it better. It could be worded more concisely, in a more eye pleasing format, and also, some simple things should be covered, for example, a classified ad, should be in regards to an item that is for sale. If it is COMMENTARY or web site feedback, then it should be automatically removed or placed in the appropriate area.
Thats the simple stuff, and quite frankly I find that boring.
If I had a site, I would have more exotic rules.
Number one, I would ban all unnecessary prolixity.
I would require the poster to remain aware of paradigm shifts. Declining optimism should not be overt.
LAAAAAAAAAAWWWWD help me,... sorry having a geek moment, my apologies to the code monkey for having to witness this....