Alright, perhaps the above image is a bit much. After all, it's not as if Steve Jobs himself has been tracking you. Rather, it turns out that your GPS-equipped iPhone or iPad has been logging your location to an unencrypted file on the device.
The device does not collect data all the time; your location is only saved when you use a location-based service such as FourSquare. Those of you who do not use those services may think you are safe, but you should remember that things like "nearby" searches also count as location services and are logged. For example, because I have location tracking enabled for Google searches on my smartphone (so that I can find nearby restaurants), every single time I search for anything my location is logged.
What's even more disturbing is that information in this file does not stay only on your device. It is also copied to your computer whenever you sync with iTunes. So, anyone with access to your computer or phone could look at a log of where you have been.
Okay, so Apple is tracking your location, and saving it to a file on your phone and computer. What does this mean? In reality, not much. Many users already choose to share their location through apps and other services, and even those who don't may not care. However, there will still be some people who take issue with this logging, especially because the logs are unencrypted.
This begs the question of why Apple is doing this. I don't think they would risk angering people for no reason, so I assume they use this information for something. For now, we can only speculate and consider turning off location services on our iOS devices.