The posting ranks have been changed and they are now as follows:

Book Worm ~ 0
Ammatuer Novelist ~ 50
Librarian ~ 120
Senior Librarian ~ 200
Agent ~ 400
Publisher ~ 600
Novelist ~ 1000
Best Selling Novelist ~ 2000

And there is one more secret rank but you'll just have to do a lot of posting to find out what it is...