Forum ranks are typically used as an indicator of that users experience / engagement with that particular community. IMHO, they're not really meant to be taken too seriously (though, it has to said that I've never been that inclined to take rank too seriously IRL - you are are your actions, rather than a title...). Depending on the forum, rank may relate to post count, length of membership, or to recognize other actions (like fundraising, or similar).

The elder moniker doesn't necessarily carry religious connotations & the poobah rank is more a playful nod to the realm of Gilbert & Sullivan.

I hearby recognize Fuzzy as 'The wisest elder ever'...