@steve perfectly reasonable to add other properties for other views on that collection.
With pump.io, for example, we have "major" and "minor" inboxes, so you can see the important stuff (creating new image) and filter out the unimportant stuff (likes, shares, follows, unfollows).
I think it'd be interesting to add some additional properties for other streams.
In general, if you want to do new things, make new properties. Fucking around with existing properties is a bad idea.