When Siri was first available, there were almost no underpinnings on it would be the next big thing or how important it would be. Suddenly, after this general release on a limited hardware, we suddenly find it the next big thing.
Now that Apple acquired them, they can use their platform to really promote it and get it on everyone's device by default, which will help a lot more people to find and use it.
I guess most of us here in hacker news would have known Siri (from Sri) from its first public release. Many of us here also would have watched that Youtube video describing this amazing combination of technology. I guess I didn't feel any magic comes from the fact that I am not living in the US (so the app means nothing to me)