How does one cancel a subscription completely and clear out all data.
You can edit your newsletter and notification subscriptions in your MyCHOW section -- 'notifications' and 'newsletters' are the two last options. You can also remove your profile information, favorites, etc from there.
Then, email the moderators at email@example.com to deactivate your account. It won't remove your posting history, and your emptied profile will remain to link those posts together.