Push-style networking has always been part of the Internet. The SMTP protocol, which is used to send emails to and between email servers, is a push-based protocol—when a server wants to send an email, it reaches out and contacts the other server. SMTP has never been used to transmit email to individual users’ computers, however, because many end-user computers aren’t always turned on, aren’t always connected, or are behind firewalls with no openings.

In 1996, the idea of using push technologies to deliver news and other information became a brief fad. Companies like PointCast tried to commercialize the technology, and Microsoft did their best to embrace/extend/extinguish it with the Active Desktop and Active Channel features in Internet Explorer 4. Ultimately, nobody found a good application for push on early Internet-connected PCs, and within a couple years the fad was over.

In 2003, RIM created the first commercially successful end-user application for push technology: Email messages, and later BBM text messages, were instantaneously pushed to BlackBerries. This was hugely valuable for customers—particularly executives and decisionmakers in large businesses, which had the resources to install proprietary BlackBerry email servers—and fueled the BlackBerry’s success.

In 2008, along with the announcement of the App Store, Apple also announced that they were going to open up a push notification system that could deliver notifications for any app, not just their own email and messaging apps. Interest from developers was so high that they actually had to delay the launch of push notifications for a year while they scaled up their systems, but in 2009 they finally launched the Apple Push Notification Service, the first general-purpose push notification system.

So Apple invented the mix of features that we now call “push notifications”—but they based it on decades of work by competitors, startups, and Internet engineers who came before them.