And you can absolutely guarantee that the three letter agencies remember every one of them. They can look at who you've made transactions with and usually get a very good idea just from that who you are. I imagine they get more from fronts and hacked/infiltrated organizations. If they need more and you've ever transacted with a commercial entity within their jurisdiction, you are a National Security Letter or local equivalent away from being identified.
This IP address thing is like discovering that the back door is unlocked and open when the front door is secured by a piece of string.