Note this is from around 1998. And it seems heavily grammar based.
Things might have changed, since the hardware has become more powerful, and some statistical techniques have proven pretty good at Named-Entity recognition.
It's possible that the current ones are still based on the work of Apple's Advanced Technology Group. Apple used HTC over its patents and this article about the suit mentioned the technology being added back in 10.5:
Apple's Advanced Technology Group had a few projects that dealt with processing text to discover information structure. Jim Miller who was part of ATG has written a few articles about the work they did:
I had to figure out how to do essentially what Apple does, and I'm by no means a computer scientist. Here's what I learned: http://blog.myinboxassistant.com/post/9613650483/experimenti...