Improving Magento product stock alert, Out of Stock notification extensions allow both customers and guest to subscribe to out of stock products. Both customers and admin can see the subscription. Customer can view all of his subscription in My Account page. Report feature allows admin to view all subscription from all customers for all products. You can also view subscriptions which customers register for one specific product by going to edit page of that product. Have a look at the Out of Stock Notification product page and start selling more with it.