I am slowly becoming convinced that the next killer app is the personal assistant app. My life is sharded between contact books and voip apps and IM and email that hardly if ever talk to each other or make my life easier.
You get a lot more integration than you probably think with Google Now. It reads my e-mail to keep track of my upcoming flights and packages being delivered. It checks out my calendar and will conveniently provide directions to events on my schedule. There's not a great level of integration for the google chat and voice features yet, but it's coming I'm sure.
Yeah, I guess if you want 3rd party integration via an API you're probably looking for Apple's Passbook. It'll be interesting to see what MSFT does here and how long it'll take for all three to merge into a similar set of features.
What we need is to simplify our lives, not to make so complicated to the extent that we feel lost without personal assistant on our wrists, pockets and in front of our eyes. This whole trend is in reverse direction. We are slapping more complexity on top of more complexity. This is only going to make people's live more complex, requiring even more smarter personal assistants. It's a vicious cycle.
Its a huge market, but space for a lot of niches.