It's where the teeth are asymmetrical, at first glance the ring looks worn out in spots. Supposed to help the chain catch in the teeth of the larger ring as you shift.

The pins are little stubby posts sticking out on the inside of the ring, at first glance it looks like someone left some bolts loose. Supposed to help lift the chain up to the teeth.

All together they make the shifting quicker and smoother.

I just wonder how important that is to the kind of riding I do (probably not too important) and to the mechanical parts of my bike (that's what concerns me, I don't want to wear anything out that could be avoided with a different ring.)