This statement from Apple is just about the only viable explanation for the data that I see on my own iPhone:
This data is not the iPhone's location data-it is a subset (cache) of the crowd-sourced Wi-Fi hotspot and cell tower database which is downloaded from Apple into the iPhone to assist the iPhone in rapidly and accurately calculating location. The reason the iPhone stores so much data is a bug we uncovered and plan to fix shortly (see Software Update section below). We don't think the iPhone needs to store more than seven days of this data.
The far more detailed “local” tables are probably the source for the “crowd-sourced” data referred to above but I’ll be digging a bit more to see if there’s anything else lurking in the system databases.
It’s still technically possible for Apple to be harvesting location specific data that could be used to track users but I really don’t think so in the light of their previous statements, the actual structure of the data* that caused this latest batch of seriously uninformed speculation, and the obvious legal risks (in California, where Apple is based) associated with tracking anything that could then be mapped to real people.
Hopefully some sanity will prevail about this issue from here on.
That’s not to say that there aren’t huge risks associated with using crowd sourced location data, as Apple admit to doing a number of times here, but at least at this stage Apple do appear to be aware of the risks and concerns and have been acting accordingly.
* So far almost nobody appears to have actually examined the data with a view to understanding [a] whether it could be used for tracking or [b] why there are so many entries with identical timestamps. I know it’s silly to expect signs of intelligence on the internet but most of the echo-chamber chatter about this was truly uninformed and pathetic.