There's no arguing that notifications are hugely important. Purveyors of operating systems, hardware, and applications all want their notifications to be informative, yet unobtrusive; useful, yet dismissable. Some are better than others at delivering the right balance. Google says bringing app-based notifications to its own Chrome brower has been a huge success. It claims more than 10 billion notifications are being sent to Web sites every single day. Chrome adoption is good, but there are plenty of other browsers around the world that cotinue to hold significant marketshare.
Enter Firebase Cloud Messaging for the Web. Firebase already supports sending messages through Android and iOS apps, as well as via Chrome. Beginning today, developers can use Firebase to send notifications to most any browser that supports the open Push API. This means Chrome for mobile and desktop (v50+), Opera mobile (v37+), Firefox for desktop and mobile (v44+) and others. Support for Microsoft's Edge browser on Windows 10 PCs, and Samsung's native browser on mobile devices will arrive further down the road.
Google believes engaging users and discovering their preferred content types should come first. The technical aspect of Web notifications is a start, but shouldn't be abused as a way to blanket peopel with advertisement-style notifications. It's important to note that end users will need to opt in to receive any type of notifications.
A Getting Started Guide is available to help developers get on the move with Firebase Cloud Messaging on the Web.