But I do wonder what a mess would result if it had collided with mass market Android and the shovelfulls of sofware that treats the notifications like a 90s systray. BBOS 10 not being Android might have been a bit of a moat against that.
With the right API, it would have been great - I don't want a notification from Instagram that friend X liked my story, but if all app notifications were segregated by user, that firehose of notifications would be way more manageable.