The piece is specifically positioned as a retort to a somewhat sensationalist O'Reilly piece, and in that context it's perhaps decent. But this headline alone on HN is at least as sensationalist - redefining "your phone is tracking your movements between cell towers with a general accuracy of 2km or less" to "your phone is not recording your moves" is just newspeak.
Argue that the accuracy makes the data less usable for nefarious purposes, or argue the (much more pertinent to my mind) point that your carrier already has high-accuracy historical info and this really just puts similar historical info in your hands as well, point out that law enforcement can easily get the carrier info without ever even touching your iDevice, but don't try to claim that this is not recording location info attached to you.
It's a long time since I worked on mobile phones but in GSM the phone has to keep an internal of the tower it's connected to and the nearest neighbours in order to manage handover smoothly (ie. With dropping calls). I suspect 3G is similar.
In GSM the phone also had to know the distances to each tower +/-500m in order to adjust the timings for communication with the tower.
(It's 8 years since I did is stuff so memory might be off on the numbers a bit :-)
I just used the original headline from the blog. You're correct that it makes sense in context, but that is why the "recording your moves" part is in quotes. It's a direct quote from the O'Reilly headline.
Anyway the larger issue is that it is not clear exactly what information is being logged. We know some location info is vulnerable, but exactly what and how much? The O'Reilly researchers really should have done a better job. The least they should have done was to run some controlled experiments with a freshly wiped phone.
First off, information is only logged when using Location Based Services. So if you never load up Foursquare or Google Maps, you have nothing to fear. Also, you can totally disable LBS in your settings.
Secondly, it's only maintaining a single record for each cell tower and updates the "last seen" timestamp. So while it can tell you the last time I've been to a specific area, it can't tell you how often or when I've been there previously.
Argue that the accuracy makes the data less usable for nefarious purposes, or argue the (much more pertinent to my mind) point that your carrier already has high-accuracy historical info and this really just puts similar historical info in your hands as well, point out that law enforcement can easily get the carrier info without ever even touching your iDevice, but don't try to claim that this is not recording location info attached to you.