The Evented API specification is a way to get the phones ringing in today's Web APIs. For real-time applications, that's critical.
I love this video of Vivek Ranadiv, CEO of Tibco because he does such a great job explaining why events matter:
Here's the quote I love best:
"They [IBM] use a data base and it's like a phone that doesn't ring. If something happens, it goes into the data base, but nobody else knows that something just happened. You have to keep asking questions. You have to find the information. With Tibco, the information finds you. The phone rings. Huge difference. It's all about innovation and it's all about knowing your customer."
A phone that doesn't ring is a great image. That's what most APIs are like. With most APIs being deployed today, you have to go ask the question. For some things that's fine, but not for real-time or near real-time data. We developed the Evented API spec so the phones could start ringing.