Push notifications are the alerts that appear on your smartphone or mobile device to let you know about new posts on social media, new website content, or other online activity that occurred while you were doing other things. There are different types of push notifications, including badge notifications – generally a number on a miniature version of an app icon, letting you know how many new messages or posts are available – and banner notifications, which feature much the way pop up ads do – appearing briefly on screen to alert you of activity before disappearing.

Amazon has just announced it is adding push notifications to its Alexa suite of products.These notifications will manifest as a green light and a chiming sound; users can also ask “Alexa, what did I miss?” or “Alexa, what are my notifications?” It is to be expected that other digital assistants will soon follow suit.

Push notifications have rapidly become a normal part of the digital landscape. People understand push notifications – even if they never call them push notifications – and have, with very few exceptions, accepted them. Push notification settings are set on a case by case basis, allowing users to pick and choose what alerts they want to receive. For example, you may opt to be notified about new Facebook posts, but not every time the New York Times posts breaking news. This allows people to manage the type and amount of content they’re being updated about.

[Tweet “Push notifications have an open rate that’s 50% higher than email.”]

At this point, you may be wondering if you need push notifications for your website. The nice thing about website push notifications is that they work on desktop browsers as well as on mobile devices. Also nifty? Push notifications have an open rate that’s 50% higher than email, with click through rates that are up to twice as high.

Push notifications work best when they feature an immediate call to action. This can range from content that a user would want to know about immediately to flash sales or special savings events of limited duration. A sense of urgency is central to push notifications: the fact you’re reaching out in this fashion means you have information your customer will want to know now.

With that in mind, it’s important not to send push notifications too frequently. If everything is urgent, nothing is. Even brands that are built on the idea of the flash sale – Gilt Group or Haute Look – limit themselves to two or fewer notifications daily.