A push notification is actually a message that pops up on user’s mobile device.  Push notification looks like an SMS message, and can reach all users who have downloaded your mobile application. Unlike SMS, push notification is free and can be send through our CMS.
It is a great tool that can be used from every business to
promote products or offers to increase sales
improve customer experience
drive users to additional marketing channels like social networks
inform for instant special discounts
and any kind of news that will help customers make a buying decision for your products or services.  Be aware that push notifications must be used in such a way of not disturbing and annoying the app user.