For me I have ranking off, as it isn´t urgent for me to become the "Queen of Renderosity". For me the stars are fun and a game. They say nothing really about an image, as often it´s a question of hard-working in the galleries only (I vote you - you vote me, and as more I vote....No sweet without swet ;-) ) A top ranking is more a question of many friends than an ace image.
There I most see images of my favorite artists only, so I always give 5 stars becourse I like their art.....