Well, it’s all over the web today: your iPhone keeps track of its general location and, by association, you. Lots of people are writing about it.
You can download a free open-source app here that will show you what kind of data your phone is storing about your peripatetic ways.
I don’t think it’s any big deal, compared to what the government can and will do in terms listening in on our calls, if they deem it necessary. There is a reason criminals and terrorists use disposable phones and change them often.
Now, back to more important things, like art.