[kh99]

Strange that there's no strategies with just post and date, but I suppose someone who hasn't posted isn't going to have much change in reputation. But I think you'd want "post and reputation and date", or else check for a reputation level that would be impossible.

Anyway I'm not very familiar with promotions, but I tested this out and couldn't find a way to make to work using just "Registered Users" and "SHY" (assuming you want them promoted out of SHY when they post) because users will just "ping pong" back and forth between the two groups. I think you'd need another user group for users registered less than 3 days with 0 posts.