Comment: Apple defends its iPhone location file

"Err, we're not tracking you (honest). It seemed like a good idea at the time - and there is a good reason that we record this data - but we'll try and be a little more careful" is the general gist of their explanation, which they posted as a Q&A on their website today.

And indeed it was a clever bit of engineering. It just wasn't fully thought through.

The US requires mobile phone companies to offer emergency services on their networks, and to do that they have to know the phone's location, so they can dispatch help to the proper location. Generally that's done by embedding GPS receivers, but they don't work in some areas - especially in densely packed cities or deep inside buildings. And it can take several minutes to calculate position - far from ideal if you need to tell the fire department where to put out a fire.

So Apple engineers figured out a faster way to pinpoint an iPhone's location, the statement explains. The phones are:

"...maintaining a database of Wi-Fi hotspots and cell towers around your current location, some of which may be located more than one hundred miles away from your iPhone, to help your iPhone rapidly and accurately calculate its location when requested. Calculating a phone's location using just GPS satellite data can take up to several minutes. iPhone can reduce this time to just a few seconds by using Wi-Fi hotspot and cell tower data to quickly find GPS satellites, and even triangulate its location using just Wi-Fi hotspot and cell tower data when GPS is not available".

That makes for a neat trick in built-up areas, with ample Wi-Fi and cell connections. But Apple hadn't considered the privacy implications or how long to store the data - kind of worth thinking through when you sell millions of units of mobile products a year that people carry with them wherever they go.