Answer:
A hole in a pole. Though I fill a hole in white I'm used more by the day and less by the night
I'm as simple as a circle worthless as a leader; but when I follow a group their strength increases tenfold. By myself I'm practically nothing.
I move without wings Between silken string I leave as you find My substance behind.
The more of this there is the less you see. What is it?
What goes through towns and over hills but never moves?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.