Edit: I also think that voice alerts make a lot of sense as well. For example, if you are an MLB At-Bat App user, perhaps you could set it up to alert you vocally when a scoring play happens, etc.
"Justin Upton homers on a fly ball to left field. Diamondbacks 4, Rockies 2 in the bottom of the 5th inning."
Wow....this would help push the boundaries of what a phone can do and how users interact with their phone even more than the already described Assistant features, and it would be very useful and pleasant for people to use (as long as there are choices on the voice and it doesn't sound robotic). I think that they will implement this and use it in the announcement. Probably as a preview, with 5.1 adding it fully.
This Assistant feature won't be flat out Siri. It will be highly upgraded, and it will be big.
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I just can't imagine "talking to my phone" in social situations. It's just awkward and a bit silly, in my opinion.
Well, people are going to be doing it and doing it a lot in the next few years. I guarantee it. It will be comparable now to when people take their ipods out in the subway and change the song. They won't be using voice to change songs, but they will be using voice to do relatively complex tasks quicker.