Shoppers signed in to Magpie can choose Save to wishlist on a product page. Each Store has its own wishlist, which can be shared with a link that shows the products but not who saved them.
When an item whose stock is counted is sold out, its product page asks for an email address. Magpie sends one email to that address when the item can be bought again. On a product's page in Store, Back-in-stock requests shows how many people are waiting for each sold-out choice.