Watchdog Customer-Initiated Restock Alert
Stop losing customers who view items which are currently out of stock. Give them an opportunity to be notified once the item is back in stock with a simple banner. Once the item is stocked, a customer will receive an automated personalized email informing them about the item's availability.
If a customer views a product that's out of stock, they're likely to purchase the item when given the chance. Now, they can subscribe to receive a personalized notification when the item is restocked and eventually purchase the product.