You are part of a large WiFi tracking network. Here are a few things you might not know. They affect your privacy in a big way.

If you are like most people, you have a smartphone. Your smartphone has WiFi. In your home, you connect your smartphone to WiFi for because it avoids cellular data charges. Also, it is faster.

And, if you are like most people, when you leave home you take your phone. And you don’t turn your smartphone WiFi off. This is because you are lazy. Or, you may want it to automatically connect at the office or a hot spot.

No problem, right? All of the wireless networks you will connect to are secure and encrypted. Your data is safe.

But what you should be aware of is that leaving your smartphone WiFi enabled allows anyone to track your location anywhere in the world. Even if you are not connected.

Here’s how this works.

WiFi in most smartphones is set to auto-connect to a wireless network. For example, when you come home, your phone connects to your WiFi automatically. But, what you might not know is that whenever you are traveling, your smartphone regularly sends out a probe looking for a network to connect to.  This is called Active Scanning. This probe contains your MAC address. Every wireless device has a unique MAC (media access control) address. In effect, it’s you.

So, whenever you are in range of any wireless access point, the wireless network records these probes and logs the MAC address of every wireless device coming in range. Anyone with access to these logs knows where you are.

WiFi Tracking Nothing to Worry About. Or is it?

Ok, well we all know that your phone company can track your phone. And it can forced to provide this information to law enforcement agencies. No big deal, right?

Here’s the big deal. Let’s say you go shopping, and pay for something with your phone. Or even just have your phone in your purse as you make the purchase with cash (of all things.) At that moment, the store has your MAC address and can associate it with your purchase or other transaction. All of the stores in the mall have been tracking you as well. They know how long you spent shopping and where, as you moved around. It is theoretically possible to aggregate your whole day of shopping indexed on your MAC address.

Don’t believe me? Read this or this. This personal tracking data is collected without your knowledge or consent. It can be aggregated and sold.

By the way, there are lots of companies selling WiFi scanners to collect your MAC address as you pass by. This is big business. Whenever I hear the word “analytics”, I shudder.