I think Google’s got this down. Their “walled” garden is not an ecosystem. Their ecosystem is the moat. OTOH, cross-platform messaging by necessity has to be cross-platform. For the sake of sales, Apple opened gates to work on hardware other than theirs. But will they open their messaging portals too?
If you think about the value of feature-rich messaging (think BBM) that is ubiquitous, they’re all just side-level value-adds. Think of it like iterative iOS improvements, like iOS6’s panoramic photo capabilities. Stuff you can live without but it’s nice to have, or a small app purchase away from having. For the most part, if we look at cross-platform messaging by technology and break it down, there are just these few layers:
1. IP (everything that requires an IP to connect to a server or something, which would include BBM and others like it, and even twitter.)
3. SMS/MMS to/from IP
By jabber-style, I’ll be super vague and include this as any sort of IP based messaging: facebook, BBM, iMessaging, AIM, gtalk, twitter, IRC, what have you.
FB, AIM and Twitter are already platforms that supports this. New generation social networks trumps AIM and other older gen networks for greater features and more flexible, better driven use cases. But for pure messaging they are probably on par (twitter at a short distance behind the pack, maybe). Group messaging is still something many messaging clients don’t get right. It’s partly what drives many to twitter and their ilk, I’m thinking.
The problem with Apple’s ubiquitious nature is how the iMessage application works over SMS, similar to Google Voice as integrated by Sprint. The added benefit of having that baked into the default text app is wondrous and multitude, except this rarely happens outside of the iOS garden–more importantly, all of this is only interesting because it is just a IP over SMS kind of a thing.
But it’s just an walled garden extension of SMS. It’s not a replacement that is built on top of it, like Whatsapp or GV/Gtalk/Gmail. So there you have it.