[isaachier]

I work on Jaeger at Uber. In short, OC is not a standard, OT is a standard. It's like asking what is the difference between HTML5 and a web browser. HTML5 is a standard for developers to use when developing web pages, allowing rendering on a number of different web browsers, whereas a single browser constitutes a single implementation. At the moment, OpenCensus is like a web browser not accepting HTML5 and demanding web developers adopt a custom markup language. If they would adopt the OpenTracing API, developers could instrument an application once, and switch between Jaeger and OpenCensus with no changes in the code. Clearly, I am biased against this approach as I have spent considerable time working with the OpenTracing project to make it the de-facto tracing API and OpenCensus is kind of breaking that.

About OpenCensus, "Open" seems to mean open source and census was the original name internally at Google (there is evidence for this in gRPC git history where it was just census). Anyway, we are waiting on OC to adopt OT, but they don't seem to be interested at the moment.