Not to take away from Google now, it blows siri out of the water, but of course you know it's "learning" based on what you search for. Pretty simple algorithm: "he searched for it once, show it again"
It's the implementation of that algorithm that makes Google now better than siri, but Google now can't just learn things on its own
I'm sure you know that already, just clarifying for those that might not.
Dont forget stalking me with my GPS too