Opinions differ.
It is easier to climb over a fence if the rails are on your side, especially if you are a child, a burglar or a dog, and traditionally the rails have been inside the property. If you walk down a road I bet you will not see a single fence with the rails outwards.
However, it is easier to nail the board on from your own side, without needing to stand on your neighbours land, and some people think the boarded side is prettier, so they have overtuned convention and created a new tradition.
Thxs for interesting info but I meant are the feather edge (which tapers on mine from right to left) the right side of feather edge is thicker on mine. Is that correct?