When you upload ranks - what does it mean to set it as aspecial rank? when its a special rank what rights do they have?

The difference between normal and special ranks is that normal ranks are automatically given to any member that achieves the number of posts required for that rank (For example a rank "Top Poster"), while a special rank can only be assigned by an administrator (for example a rank "Special Member"). If you make a special rank leave the "Minimum posts" field empty, otherwise type the minimum number of posts you want for that rank. Once that number is reached by a member he will automatically receive the rank.