The experience system of SSSB is quite simplistic yet functional. It is broken into two parts, Regular EXP and Strife EXP.
Regular EXP Edit
1 post on a forum equals one exp.
Strife EXP Edit
Strife is given out equal to the level unless they are 5 levels above or below. Below makes the exp halved. Above is 1.5x until 10 levels above, then it is 2x.