Last week, the ACLU wrote to the CEOs of the nation’s major cell phone providers asking that they stop routinely collecting and storing data on their customers’ daily movements.

Our cell phone companies know more about where we are throughout the day than our closest friends. One of the byproducts of the way cell phones work – staying in constant touch with the nearest cell tower – is that our carriers can tell roughly where we are.

And over time, that data is getting increasingly accurate.  But the major carriers – AT&T, Verizon, T-Mobile and Sprint – don’t just know where we are from moment to moment.  They also retain detailed data about our location for extended periods of time, as we learned recently when we received this document in response to our national public records request on how the authorities are using location data. The carriers also readily share the information they gather with government agencies and law enforcement.

You can help.  The ACLU has created a petition page to tell your cell phone service provider that you demand an explanation of the information that is kept about your account, when and how it is shared with third parties, and an easy way to control how long your private information is kept.