Don't quote me. I can't see anyone profile that has zero posts. Chances are you need to have some posts in the heart of the site. Which include sucky customers, brain burps, general work chat, unsupportable, cursing out coworkers, morons in mangement, sightings.
As for how many if I'm right, I don't know. Most likely til your out of the mode when the mods check your posts first.
Just a wild guess.