Among other things, it signals that all has been forgiven after the anodyne cake incident. Phew.
Also, no one gets drunk when Mrs. Allan is the hostess.
This is another vignette/not-much-plot chapter. What we get to see is a snippet of Anne growing up -- a little bit.
"That is the first time I was ever called 'Miss.' Such a thrill as it gave me!"By the way, the two poetic allusions in this chapter show both how effectively Anne has spread through the world, and also how well Montgomery knew her stuff. A quick Google search for "spirit and fire and dew" (Robert Browning) and "deeps of affliction" (John Owen) turn up just as many pages about the book as references to the originals.
"For Anne to take things calmly would have been to change her nature."
"Marilla had almost begun to despair of ever fashioning this waif of the world into her model little girl of demure manners and prim deportment. Neither would she have believed that she really liked Anne much better as she was."