The post counts go something like this:
1 - initiate
25 - acolyte
50 - speaker
100 - supporter
200 - counsel
400 - advocate
600 - campaigner
800 - emissary
1000 - herald
1500 - champion
2500 - lord advocate
5000 - Apostle
7500 - Ascendant (Added in 2018 when someone unintentionally hit those numbers)
Might be some more than that but don’t really know. There is also the Praetorian title which represents playtesters.