[BBell]

What is a “child pornography IP address registered to someone else”

Probably just crappy journalism.

[palmer]

The writeup is terrible. The most likely scenario is what I just described in my previous comment. The "child pornography IP address" is simply an address harvested from a server log. In the home router scenario that is the address of the router. It does not and cannot identify the particular computer on the home side of the router.

The phrase "registered to someone else" simply means that the router did not belong to him and "registered" is the wrong term. The correct phrase would be "automatically assigned by the network to the router belonging to someone else which he got routed through along with the other residents"