Wow, I can't believe I didn't notice. Happy Birthday dryoyo
A global moderator is basically someone who is able to edit, delete and lock anyone
's posts. He has a lot of power, just less power than the Admin.
A Forum eXpert is basically a form of recognition to people who have helped out at the forums alot. They don't get any awesome editing powers, but they are recognized. And if they are chosen as eXperts twice, they become section moderators. This is like a global moderator, but to only one section of their choice.