http://www.today.com/video/your-smartphone-may-be-tracking-your-every-move-435607107541

 
Basically all of our phones are tracking the common places we go, and there is a way to see exactly all the locations you have been over the past MONTHS including the date you were there and how long you spent there!  

If you have an Iphone go to-

Settings ->
Privacy ->
Location Services ->
System Services ->
Frequent Locations ->

Click on the name of the city and you will see a map like the one in the photo below showing where you have been, and if you click further you will see the dates and times you were there! Scary stuff! Luckily only someone who has your phone in hand (and knows how to search this way) can see it where you've been.  

If you want it gone, click Clear History and turn the Frequent Locations Button to off!  

The android tracking is a little bit more difficult to find/turn off because the phone menus aren't all totally similar (and sidebar the android tracking is actually way more scary because it reports all your locations to Google so someone online can access your location from their computer and not need the device in hand).

Here's how to turn the android tracking off- http://www.today.com/video/how-to-turn-off-android-location-tracking-435573315637 (I have the Galaxy S4 and my path was Settings -> More -> Location -> Google Location History)  

Just didn't want anyone to get in any trouble for being somewhere they shouldn't (even if it's at a bar with friends when you said you were working late, lol)

Have a Great weekend!