Now, I've noticed this before, always when I was on the way to work or something where I had an appointment on my calendar with an address in it, my iPhone would estimate the time it would take for me to get there. But today, I had nothing on my calendar, so how did it know where to estimate my time to? So I thought about it.
I went into there today and I noticed for the past several weekends my family went north to go to the mall, shopping, or something else near Newark, DE. So the iPhone remembered that and said "okay, well, today is Saturday, so I am betting you are going to go to the mall today." And it gave me arrival time to that location.
I think it's handy, borderline creepy, but helpful.
So, I went to a different mall today, in a different direction. Just to screw with my phone.