From time to time, you may find that you have run out of stock of one of your products. When this happens, customers have the option to be put on a waitlist that will email them when you replenish stock. You will also get an email that lets you know someone has placed themselves on the waitlist.
This is a way for buyers to bookmark products they are interested in until a later time. You will not receive an email when someone adds themselves to the list, but you can see how many have added the product by going to your product page.