RDF is a lumpy half-cooked potato, cold and uninteresting, complex but not satisfying. Now to me as a product developer, I can't wrap my mind around something I can't use. I just can't do it. The first thing I do, before I consider the problems of file formats and extensibility, I look at what I want to use, then I create something, seek feedback, and iterate towards something that's usable. There's a lot of hard work in that iteration, and imho, until you start doing that you haven't even started to create something.
Formats come later, first comes utility.
Anyway, as a larger question, we need a Howto. In the past I've just developed and published the results of my work. I think it's been of some help to the W3C to have unpatented prior art. With Apple it used to bother me when they'd take over my ideas, but now I've factored that into the plan, I expect to be overridden by the platform vendor. They're slower, so that leaves us a window to get our stuff established while they cross the t's and dot the i's, and get buy-in from the famous technology companies.