The other day I had a very unexpected encounter with the semantic web. I was driving to a business location that I had never been to before. I opened up Google Maps on my iPhone and entered the business name. Google Maps finds the establishment and sets the route and begins turn by turn navigation. So far pretty routine.
What happened next was a total surprise. Google Maps then informs me that I would arrive at the destination 5 minutes before the business opens. The application "knew" my destination was a business establishment, and  its hours of operation. Given additional information:  the current time  distance to my destination  my speed, it could reason that I would arrive early. I haven't figured out exactly how it did this, but I highly suspect semantic web technology is at work. I found this interesting resource.