It is similar to ranking in a game. The higher you go, the more it takes to reach the next rank.
Try not to think of it as a ranking system though. Just come to the Forum with ideas and comments that are productive (mostly) and contribute to the community. It is not to say you cannot have fun.
Look up the Forum guidelines and try to stay within the bounds. I am not a moderator, so you don't have to listen to me at all, but I just felt like sharing some advice.
No trolling, and no spamming! The interpretations of these are loose at times, but most of us try to contribute for the better, and not just post that we have "ranked up".