I wasn't thinking a lot about different formats and properties. The idea was to get out something as simple as possible. This is just afternoon hack to see if there is any demand for it.
In all honesty, I don't completely see how "a new standard" matches with "just an afternoon hack". If all you want is measure demand, why not write a blog post "Let's make a standard for job posts!" to convince people? Worked pretty well for the markdown guys.
Standards without any effort behind them are worthless. As you can see in this thread, many people feedback the standard (which clearly needs some work), not the concept.
I wasn't thinking a lot about different formats and properties. The idea was to get out something as simple as possible. This is just afternoon hack to see if there is any demand for it.