Question about the names

What is the "Neuron" "Proton" etc?
and what are the requirements to level up?

and how do you delete a post?

The titles of "neutron", "proton", and so on hint at your post count. The higher the mass of the object in your title, the more posts you've made.

I don't think you can delete your post, but you can edit it and erase all the contents - replace with "nvm" or something. You can also ask the mods to delete your post.

Here is a list of all the ranks and how many posts it takes to get them:
http://www.southperry.net/forums/showthread.php?t=6396

Keep in mind that posts in the Social section do not count. Posts anywhere else should count... unless they haven't been telling us the truth xD