What does the scaffold represent to the puritan community in The Scarlet Letter?

The scaffold, in Puritan society, was a place of public penance. This is where many punishments were carried out and this place was chosen for that task because it was very public.  Since it stood up above the crowd, most people could easily see the person being punished.  Punishments varied from a simple public announcement of a person's sin/crime to some very severe physical punishments.  Thus, the scaffold becomes the symbol of humiliation and punishment.