I added a system of badges to SMF a while ago, though only two are defined now. Here are the current badges:

Bitcoin expert	Dev&Tech only. People with this badge know enough about the Bitcoin network to reimplement something very like it from scratch. They are capable of intelligently discussing the Bitcoin network: current protocol, possible attacks, proposed changes, etc. Criteria: Recommendation by an existing Bitcoin expert or core dev and approval by a forum administrator.
Bitcoin-Qt core developer	Dev&Tech only. These are the core developers of Satoshi's Bitcoin client. They are listed here. Core developers are among the top contributors to Bitcoin-Qt, and they are all bitcoin experts, though they don't also get that badge.
Troller	Awarded for people who keep spreading FUDs, misinformation, conspiracy etc.

A core dev does not "outrank" a bitcoin expert (or vice-versa), and it's possible for someone without a badge to contribute meaningfully to a discussion with experts and core devs.