This thread is absolutely ridiculous.
First of all, this rating system is inherently subjective and also completely unnatural (not to mention immature). I really dislike the scale and don't use it, a girl is either a 'yes' or a 'no' for me, and I calibrate from experience, knowing how certain archetype girls respond best to what actions. People will always be exaggerating based on personal bias. This bias could be the need to look cool in front of peers, or it could be due to the excitement of possibly closing a very good looking girl, or it could be an infatuation with this person and can only describe it as a '10' because she has that type of power over him.
Seriously, I don't really care when people throw around numbers like this. I know that it is all skewed, and a 10 for you might be a 6 for someone else. Besides, not only is the scale subjective, but so is our sense of beauty. What I hate to see is threads like "so I banged this girl. Seriously she was SOOO hot! HB10 for sure. Anyways my question..." Do you really need that ego boost and validation from other people you don't even know reading about how you laid the hottest girl in the world? It's unhealthy for you and it's misleading and at times destructive to those reading.
This is like a penis measuring contest, except that people measure their own penis and report it and everyone trusts that you are telling the truth. If every person before me said 9 inches, then what are the chances I'm going to tell the truth (and confess to my footlong

)? I say just leave out ratings entirely as they are meaningless without well defined limits, standards, and suspension of personal bias.