Today I read the remarkable article in the Computable that according to Gardner EDA (Event Driven Architecture) will be the successor of SOA (Service Oriented Architecture). That would suggest that EDA and its technology is newer than SOA or that EDA tools will replace the current SOA-tools. Well, I'm not that into the History of ICT. But about three years ago Oracle introduced their Enterprise Service Bus as part of the SoaSuite. You could consider the ESB as the succesor of Oracle's InterConnect in J2EE technology. Remarkable also is that you can find Oracle Workflow's Business Event System parts in the ESB technology. The Business Event System (the name sais it all) is part of Oracle Workflow since version 2.6, that was introduced in 2001 if I'm right.
Oracle Service Bus (fka. BEA's AquaLogic Service Bus) was introduced in 2005. And there are serveral other service busses maybe with an even longer history.

So Busineess Events could be (and should be) part of our applications since a long time. In fact Enterprise Application Integration (another Three Letter Acronym or TLA), is about firing and receiving business events from applications.

I believe that EDA does not succeed SOA. In fact SOA is about Services and Services on their own are not usefull. Services are triggered with an information object. And this infact is an event. Connecting Services in to a business flow (what we call "orchestration") is about passing Business Events between Services folowing a Business Process. Nowadays we tend to do that using BPEL or BPMN.

Therefore I would state that SOA = EDA + BPM. I must confess that I did not make that up on my own. Since I'm a former Oracle Employee, this is what I've learned from the positioning of Oracle's toolstack onto SOA.

Having a Service Bus is not a replacement of your SOA toolstack but a very valuable addition to it. It's a very good idea to have a Service Bus abstract your services from your Business Process. That makes it easier to do things like aggregating services, replacing services, transformations from Enterprise Business Objects to Application Business Objects, etc. But this article is not about the value of an Service Bus. For that I could write a complete separate article.

Read also this previous article.