WP's site helpfully tries to show "this person's other phone numbers". My guess is it's acquired via credit institutions when you use that number for 2FA with a bank (since honestly, what the hell, virtually no bank supports U2F/TOTP 2FA and demand phone numbers, ugh)
I don't know how they match it in the backend, often it's wrong (and results in innocent parties being attacked).
I usually recommend completely prepaid lines for this to prevent hijackers from using the good old social engineering trick to hijack their accounts via customer service by providing last 4 of various identifiers. But these still eventually show up after you add the number to enough 'traditional' accounts. One of my friends (female, streamer) has gotten police at her house at 3 am with guns drawn so many times it's ridiculous. At least in many parts of, if not the entire US, trying to swat someone is legitimately trying to do your hardest to murder them.
This honestly should be made illegal, there is no reason for these services to exist, or for public records to be made available at all other than rate limited, in person without the ability to take a copy. Exceptions can be made for elected officials.
I checked and it appears they lack Canadian data; and so perhaps I was correct in presuming that such egregious breaching of personal privacy would be troublesome up here. Or maybe WP just doesn't have the data.
FWIW, there are cheap providers of SMS over SIP, now. I have a DID through voip.ms that can send and receive SMS, and it's cheap.
I don't know how they match it in the backend, often it's wrong (and results in innocent parties being attacked).
I usually recommend completely prepaid lines for this to prevent hijackers from using the good old social engineering trick to hijack their accounts via customer service by providing last 4 of various identifiers. But these still eventually show up after you add the number to enough 'traditional' accounts. One of my friends (female, streamer) has gotten police at her house at 3 am with guns drawn so many times it's ridiculous. At least in many parts of, if not the entire US, trying to swat someone is legitimately trying to do your hardest to murder them.
This honestly should be made illegal, there is no reason for these services to exist, or for public records to be made available at all other than rate limited, in person without the ability to take a copy. Exceptions can be made for elected officials.