Short answer? You appreciate context over content. Anything and everything can be content. But not everything can be contextually meaningful.

Take what I had for diner. Should I post that on HN? Absolutely not. Not contextually relevant. What about a blog post on Angular JS modules? Now that makes sense.

If facebook has a context like HN, or a meaningful way of identifying it like Reddit, then it has been lost on me. I mean, facebook's context is that it's an address book for your local social group right? So that must mean the context is contextually dependent on that right? I don't think that's 100% true. Facebook imparts it's own context. Which is basically sharing is caring. So it's context is basically content!

Long answer? Not sure...