Significance of the tale...
The story is about revenge and showing how karma works, when you do bad you cant expect good. The story was told because the Reeve was upset over the Millers story about a carpenter, so he told a story of a Miller getting what he deserved for stealing. Although in the Canterbury tales everyone knows the Reeve was just telling a story, this still happens today with rumors made to get revenge on somebody. The irony is that the two students were told to "grind mill" for the miller so that the Miller couldn't steal but back then "grind mill" was another term for sleeping with.