Push Notifications - sometimes referred to as Push Alerts - are direct messages that pop up on phones that have your app installed (and have given permission for you to send them messages).
You can send Push Notifications directly from your Dashboard.
You can also create categories for users to opt-in to, so that they may receive targeted alerts that are relevant to them. For instance, you might be a fashion brand, and create a category for kids' wear - parent may then opt-in to receive kids specific promotions, should you wish to target that demographic specifically.
Push Notifications are a great tool for informing users of changes to your offerings; new products or articles; promotions; or even just to say 'hello'.