I remember a few years back using a similar app as Siri on my BlackBerry Curve 8330. The accuracy wasn't perfect, but it was the closest thing in comparison with the built voice recognition software. If you've used a BB before, it always started out with "Say a command ...**beep**". Anyways, I used it to Google where I would have my next lunch break. Other than that, it wasn't all that useful.
Earlier versions of the iPhone have simple voice commands too. I never knew of anyone who used them. I'd imagine they were invaluable for the disabled though.
That being said, Siri's real strength is the ability to parse a sentence of natural-language speech and proceed with a multi-stage response. The kicker is that it's really just manipulating a few pieces of info that other apps use all of the time. The people you've texted recently, your address book, your current location, etc.
As annoying as Apple can be sometimes, I have to give them credit for taking a piece of advanced technology, and using it to bind together a bunch of things that already existed, and make them work better together as a unified whole.
- "Hey Siri, wake me up at 8:30 tomorrow"
Siri sets an alarm for 8:30am using the alarm tone you last used. You can specify AM or PM, but otherwise she'll assume you want to get up in the morning.
- "Let Lisa know I'll be late."
Siri figures you're probably trying to text the Lisa you message the most. She writes the text "I'll be late." and offers to send it.
If you've never texted any Lisa before, she'll ask which one you're talking about. She might ask the next few more times you try to text Lisa, and eventually stop asking.
- "Remind me to thaw the chicken when I get home."
Siri is aware of everything in your address book, along with your current location. An alert will pop-up when you get home telling you to "Thaw the chicken."
Again, nothing crazy advanced at work, except some really nice noise-cancelation features and better language parsing than we've seen on a phone before. The other ingredients have been in place for years. It's how they've made them function together that matters. Apple is less about selling you a long list of features, rather than a package that does a shorter list of things very smoothly. You're not talking to a phone, you're just talking. Not "Make new calendar entry. Doctor appointment. 10 am January 20th." but "Remind me to go to the doctor at 10 am on the 20th." It's a subtle difference, but an important one.
How people interact with their computers is just as important as what those computers are capable of.