Many sites and forums use HTML5 web notifications to show push notifications in browser, even when browser is closed.
in operation systems like Windows 10, the notifications show up as nice banners in the notification center, it helps to stay in touch among other benefits.
please implement this feature in Microsoft Tech Community.
related and useful links:
https://www.bennish.net/web-notifications.html
https://www.w3.org/TR/2015/REC-notifications-20151022/
https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API/Using_Service_Workers
https://developer.mozilla.org/en-US/docs/Web/API/Push_API