When you reach 20 posts you get avatar privileges and a larger signature space and can upload images to the gallery.
When you reach 50 posts, you get even more signature space, and private messaging and emailing is enabled.
You need at least 50 posts for your profile page.
You also need 50 posts to post links. You may not post links to personal business sites or personal websites with advertising or websites that are in competition with MiniMins.
I hope you understand the privileges that you will receive for being a long term poster.