Honest question, since I might be out of the loop here in Europe, but what user engagement pieces does Amazon have then ? I use Amazon for shopping and AWS, and would have no idea what other products they have that are dominating a market. Is this about Kindle ?
If you're going to launch social, you could do a lot worse for a starting point...
And in a broader sense, I'm much more optimistic about building a social network to unify disparate features that people already love, vs imposing one from the top down (e.g. G+). FB only got away with the latter because of being first, and seems to be pivoting to backfill as much functionality around it as quickly as possible.
Well they do own twitch & good reads, right?
Sounds like they really want in on the communication game.
Whatever gadgets they might hang off the app, they're fundamentally a way for people to talk to each other. If you don't have the people, why would you need a slick implementation? As you mentioned, the app would go out of vogue and users would move on.
Amazon making a bid here sounds like a play for a decent social seed, likely steming from users of its core properties (shopping and dev). Of all the mega-corps, Amazon is one of the few that has all the pieces and user-engagement, but no social component.
Which is ironic, because their properties would play a lot better with one than, say, Google or MS. And starting with something like Slack (bottom up vs top down) is an interesting move.