“Why is it that when one man builds a wall, the next man immediately needs to know what’s on the other side?”
- A Game of Thrones

OK R.M. here we go.
You are correct “user titles” are determined by post count.

User Titles -
Junior Member 0-29
Member 30-99
Full Member 100-299
Top Member 300+

Non-Rev Correspondents are Forum members who have a wealth of nonrev travel knowledge and a willingness to share tips and advice and to help their fellow traveler navigate those often ‘bumpy” non rev skies. They go that extra mile.
Each correspondent specializes in a travel destination (usually their home base and/or a destination they visit often) or targets a non-rev travel niche.

Moderators - They’re the ones with the whistle and clip board
Administrators - Have the whole bags of tricks
Duties of moderators and administrators- to stock the shelves and clean up the spills in the aisles.
In other words - to keep things running smoothly.