We are imagining different things. I'm trying to build an isolated layer wherein the content is opaque, and there is a kind that specifies whose social media specification protocol this record belongs to. If someone wants mime-multipart content or whatever, that is the next layer up from what I care about, opaque at the layer I'm concerned with. Now if any application has specific needs from the lower layer and they are general and apply to multiple applications, then I need to think about that.