Yes, good points, but at the moment we are seeing the Steemit tag-streams having content from every platform - zappl tweets mixed in with video links etc. We haven't yet reached the point of the "I'm on the bus home now" micro-message, but that surely will happen if that platform becomes widely adopted.

So if the consensus is that Steemit *shouldn't* become the blockchain aggregator, then all the more reason to add (as you say) a filtering system so that different *types* of messages can be differentiated.

I think we're heading in the direction messages are not always going to be actual posts, hence my idea that this should be discussed before it becomes unmanageable for many users.