The original question had to be edited.  The Guild is a group of White people in Centreville that is trying to mobilize the community against the fledgling organization of people of color.  The Guild was designed to mobilize the White community into continuing the Status Quo, silencing any possible outrage resulting from the Till murder.  "Going door to door" and increasing its membership in the town, the Guild is an active representation of how Whites in Centreville were not passive in the racism that African- Americans had to face.  Many of them were active participants in continuing a system that Moody would come to hate:

A few days later, I went to work and Mrs. Burke bad about eight women over for tea. They were all sitting around In the living room when I got there. She told me she was having a “guild meeting.” and asked me to help her serve the cookies and tea.... When I heard the word "nigger," I stopped sweeping and listened. Mrs. Burke must have sensed this, because she suddenly came to the door.

The significance of the Guild meeting bears much impact on Anne.  Its meaning to her is that at a point when Moody is coming to terms with who she is and how she interacts with the world, she recognizes that there are White people, such as Mrs. Burke, that deliberately wish to keep people of color in a socially stratified position.  The Guild meeting coincides with Anne's understanding of the NAACP, which could be seen as a type of "guild" for people of color.  Anne's understanding of the Guild and its purpose coincides with the sentiment that opens chapter 11:  "I was fifteen years old when I began to hate people."