In English:
Again IIRC, the threshhold for level 1 is 50 posts. After that, the threshhold doubles for each successive level.
Spelled out: for level 2 it's 100 posts, level 3 it's 200 posts, level 4 it's 400 posts, level 5 it's 800 posts, level 6 it's 1600 posts, level 7 it's 3200 posts, level 8 it's 6400 posts, level 9 it's 12800 posts, level 10 it's 25600 posts, level 11 it's 51200 posts, and level 12 it's 102400 posts.
Why do we have so many levels?
