[danShumway]

GP's "directly" is a pretty large overstatement, but at the same time I've noticed something of an uptick over the past couple of years of people saying that IP addresses aren't PII or that people shouldn't be concerned with them getting leaked, and I just don't think that stands up to much scrutiny.

If IP addresses didn't matter for privacy, Tor routing wouldn't exist. If IP addresses weren't useful for blocking specific users, IP bans wouldn't exist. If IP addresses weren't useful for tracking, operators wouldn't have gotten up in arms about Apple's private relay service. Obviously this stuff matters.

Remember that not everyone lives in or around San Francisco. For someone in a suburban/rural area, an IP address combined with things like timestamps, user ids, and the text of the edits can go a really long way towards unmasking them. Even for people who live in more urban areas, it is still obviously easier to find someone who lives in San Francisco than it is to find someone who could be living anywhere on the West Coast. If they could also have been using a VPN, or time-shifting their posts... that makes it even harder.

In contrast, how hard do you really think it would actually be to get some address data from a voter roll or via a warrant or even just through one of the scummy person lookup services online and to iterate through everyone who shares that IP address and check to see how many of them are named Pietri? Or who have shared the username wpietri across another account, or posted somewhere else at roughly the same time? Your IP address is drastically reducing the search-space for other attacks, many of which (timing, text-analysis, etc) are impossible to get rid of when making a Wikipedia edit.

[wpietri]

I agree IPs are PII, and that they can lead to unmasking. I also agree the person I replied to was wildly overstating things.

But for the current context, where we are talking about whether or not user account registration is helpful in preventing abuse, I think the kinds of low-probability, long-timeline consequences you describe are not really going to deter most would-be vandals. Especially since Wikipedia is going to know the vandal's IP address whether or not it gets show publicly. So I think Wikipedia is still a good example of how "no user accounts" is workable at scale.

[danShumway]

That's totally fair. In the context of preventing abuse, having an IP address on Wikipedia is definitely less useful to them than having an IP address + an email + whatever other verification methods services are throwing in front of accounts.