November's full moon that happened for past three days (including Thanksgiving) has always been a signal of the changes to come. As the last full moon before the Winter Solstice, it's seen as the final bit of light before the darkness of winter. It's also known as the "Mourning Moon."
Many modern-day superstitions surround the moon in general. The full version has long been upheld in Paganism as a time, every month, to reflect. People who follow Pagan traditions spend the autumn preparing for the colder months. The final step in this process is the letting go of old things — what we must leave behind before we reach the new year. Hence, the "mourning."
Cleansing rituals are conducted in observance of the Mourning Moon. Discarded things can be anything from the most frivolous—like nail biting or chewing on pencils and pens—to deeply profound (the grief over a lost loved one). What the point is, to think of these things one last time before moving on from them. Make a list and drown it in a jar of water (the element is associated with this full moon). Or you can perform a modern version by adding your list to a note on your phone, and then delete it.