I see. Well it's a solution.
I'd propose a solution d (or c.2) where the user makes these announcements in a separate kind, The follower would then have to actively query for notes of this kind to get knowledge of other stuff the microblogger wants to share.
Right now, my working solution to this problem is separate keys. People want to follow your 130 char tidbits, follow this key, they want your long form, follow another, they want your videos, that's a different key, etc. It's not too cumbersome especially if you pick one (your kind 1 publishing key for example) as your canonical identity with the information on how to follow your other stuff in your kind 0.
