In the UK we also have a system called TrafficMaster [trafficmaster.co.uk] which analyses traffic flow for their satnav services. There is, however, nothing to prevent them working with the stores to cross-reference number-plates against traffic flow. So now the store can find out exactly where you're driving as well.
That kind of information is something I never signed up for & one of the reasons I'll never have a store loyalty card.
Watson is given the "answer" (remember it's Jeopardy) as textual input at the same time as it is read to the other contestants. It then figures out all the likely questions along with the likelihood of each of them being right. Only once it's figured out which answer it's actually going to answer will it buzz in.
It won't use the additional time which a human has after they've buzzed to continue to think about the problem - unlike the human competitors.
The thing about Jennings is that in the end he just buzzed for everything because he was so confident he knew he could figure it out during the thinking time. Consequently if Watson is to win it's got to come up with the right answer in the time it takes for the question to be read and the reaction time the other competitors will take to buzz. This'll come out at ~ 3 seconds.
When you think about the problem like that, all of the crap people are spouting about "it gets the question as text rather than _hearing_ it" and "it's got a huge database to search" becomes moot since it's got to so much to do in just 3 seconds!
egrep patterns are full regular expressions; it uses a fast deterministic algorithm that sometimes needs exponential space. -- unix manuals