Difference is thin, as between "automatic", "fully automatic", "intelligent" or "smart" systems. Or as between "programmer", "developer", "software engineer".
Ops team may create an automatic solution, e.g. script to call with parameters and a runbook. DevOps will create fully automated solution, without need for a runbook.
By definition, DevOps is developer, (an one who uses Agile techniques, such as automated test cases, CI, source control systems, ticket management systems, etc.), who is able to do Ops tasks with code.
You have a different definition than I do. I'll copy-paste Wikipedia since it matches my understanding:
> DevOps is a set of practices that emphasizes the collaboration and communication of both software developers and other information-technology (IT) professionals while automating the process of software delivery and infrastructure changes.
DevOps certainly does not mean that Dev has to do Ops now, too, although it's frequently misunderstood as meaning that, and IMO that usually leads to a lot of tears in the long run.
Wikipedia quotes description of tne conference, not a description of DevOps role. However, if you read carefully original article, you will see that main idea was to close gap between ops and dev team by bringing dev techniques, such as Agile, to ops team. So, DevOps IS developer with Ops knowledge.
