Most ISPs use dynamically assigned addresses
they're next to useless unless you can cross-reference them against the ISP's records.... which only a properly appointed authority can
Just because addresses may be assigned dynamically, doesn't mean there isn't any persistence - plus, I suspect for those persuing this, they are probably reporting it as a crime, and with sufficient interest by the police, IP addresses used at the time may be of use, and would almost certainly be traceable by ISPs.
Yes, but there's little point in internet detectives trying to work out where he lives from them.
I disagree - whilst some quite savvy people could obfuscate, most don't.
So IP address may well reveal coarse-grained location, and other information and types of searches may be more revealling.
I wouldn't be suprised if several people in this thread, have some real idea on name and address, or at least some quite tenable location info.
Posting name and details of person responsible for the IP address (/ ranges) is probably an irrelevance, and contamination the thread doesn't need, outside of that, though - many people - quite possibly the subject, here, may not be so informed as to realise how much info can be derived from scant details from, say, email headers, or originating IP addresses and other searches possible once you have a couple of details.
That info, present in this thread, may well be something of an incentive to the subject, in terms of resolving this - let's not forget that whilst being skeptical.