In addition to what everybody have said, I will like to throw a little light on this topic of discussion that "smerit" is a product of merit, and as such it increases directly proportional with an increase in the original "merit" which can only be given from a different forum member, that can never decrease no matter the circumstances unlike the forum rank feature which is object to both "Activity" and "merit". And as such there are certain merits a user need to attain to arrive at certain rank, that is;
1 merit = Jr. member
10 merits = Member
100 merits = Full Member
500 merits = Hero Member
1000 Legendary Member (i.e that last rank)

While more can be seen in the link provided by tranthidung below