A few examples:
I was in San Francisco last week to cover Google I/O and meet with some other companies in the area. I had a meeting in Mountain View on Friday morning. Google Now sent me a notification about 45 minutes before my meeting that said I should leave if I wanted to make it on time. It even took traffic into account. Incredible.
The other night I was getting dinner with a few old journalism friends from college. We were talking about Jim Romenesko, and one of my friends wondered how old he was. I asked Google Now, "How old is Jim Romenesko?" The answer came up in less than a second.
I'm a Mets fan (unfortunately), so a lot of my sports-related Google searches are for the score of the latest game. Google knows this, so Google Now automatically sends me notifications with the latest score. I don't even have to ask anymore.
I took the red eye back to New York Friday night, and spent the hours before my flight drinking with some PR friends in San Francisco's Mission neighborhood. Based on my search history, Google Now already knew my flight number and kept me updated with gate information and potential delays.