You can enable your customers to subscribe category alerts by email. Choose whether to enable users to subscribe to it, and select the email template to use. Also, select a sender display name, which applies to category alert types.
When you add new products to your Magento store, it would be useful for your site if the product information is sent to the customers who have subscribed to your product categories before. Owing to the subscription option, customers will receive new product information without visiting your site and if they are interested in your products they can go to your site again and buy them. It is believed to be a good solution to keep your customers updated and get more profit
Magento Category Alert is a good utility for your site, Magento extension will help you to increase interaction between customers and your store by automatically sending new product information to the customers via email.