As you can see in the previous reply, this merit can be interpreted as a motivator for yourself to be able to post something of quality. The merit system was put in place because the admin had discovered that tens of ton of junk and worthless post kept flowing around here non-stop.
Thats why this system support anyone who post quality good. This system can limit spam poster from rank-up and will not prevent anyone from rank-up if they can make a good contribution to the forum. When you care about forum then other user will care about you. Useful writing has the potential to gain more merit for author recognition, and established Legendary member can generate more merit because they have better knowledge and experience than others. You can also do what they do if you want, hone your skill and knowledge and start now.
You are granted merit from other members when creating content or a useful response to topics, and this merit helps you develop your account in the forum and when you are granted that reputation you can give other people half of this merit, for example if you get two, you can give one
In my opinion this has been explained hundredsl of time by other, its just that beginner dont want to know because of their habit of rarely reading sticky thread.