This is not new information, just something a lot of people are not aware of. If you already knew this, good for you.
If you use an andriod phone, log into your google account on a desktop or whatever and search "location history." If you have your GPS turned on on your Andriod device, Google keeps a running history of where you've been. This can be pretty cool as it can give you a running minute-by-minute review of the various stops you made while you were on that trip to NYC last Christmas.
However, it there are certain stops you've made to a certain hotel or strip mall or whatever that you didn't think anyone knew about, maybe it isn't so cool.
The good news: you can edit your history to a certain extent.
It's far from 100% accurate, but it's close enough to raise some red flags if someone knows what to look for. Personally, I just drop down the menu on my phone and turn off the location if I'm going to be heading somewhere I'd rather not be seen. YES I KNOW THIS ISN'T FOOL PROOF.
Just food for thought.