I wondered about that too.
There's Sr. Member, Jr. Member, Full Member and Newbie, but it seems to be related to the number of posts, which is also indicated.
I suggest moving the number of posts for Sr. Member up, since I am technically one of them, but I sure don't feel like it. More like Jr. Member.
I suggest also having a poll/ thread of most trusted people. And a list of the ones we should avoid.