You might see Minecraft Forum which levels you up with how many things you comment on. Or other websites, where there is no experience at all. Why is it HERE? Why, only Planet Minecraft?

For MY opinion, I think that it is here to encourage posting anything! The idea of getting famous because of your builds, blogs, skins, is quite an amazing idea! It can also act like a reward system. The more you post and CONTRIBUTE to the community, the community rewards you back with DIAMONDS which increase your exp greatly. It represents how good you are doing something, how much people appreciate your posts, how... AWESOME or NEW you are! It's like a game on the website. Level up, unlock more features, respect, or even a Moderator position. For example, I just went lvl 10 a couple days ago and got permissions to join PMC's white listed server.

Ahh exp, the classic way to get somebody's attention. Now you know, that Planet Minecraft is very awesome thing where people gather and the website itself encourages everyone to post stuff. No matter what level you are, or where you started, we will all know that EVERYONE... was at level one.