Reading some of the comments here about entering your phone number on this site, I don’t believe there’s as much as risk as people seem to think. If the site we

Reading some of the comments here about entering your phone number on this site, I don’t believe there’s as much as risk as people seem to think. If the site were asking you to enter your username and password to check if it’s on a pwned list, well, yes, that would be a dumb thing to do. But a telephone number is telling the website operator at most that the phone might be associated with you, but all he learns about you is your IP address and possibly your browser fingerprint. He doesn’t get your name, Facebook ID, email address, interests, password, or anything else. Now you might say that he can see your Facebook ID or email address in the list of leaked data, and possibly through the Facebook password reset user interface as well. But he could have done that anyway without you ever having supplied the phone number. He has the entire leaked list and it seems that pretty much anyone can get the leaked list with modest effort. Furthermore phone numbers by themselves carry very little information because they are not sparse. If I give you a correctly formatted 10 digit number like nnn-nnn-nnnn, there’s a quite good chance that it’s a working North American telephone number. By correctly formatted, I mean that it has a valid area code, that the prefix doesn’t begin with a 1 or 0, that the prefix is not 555 (that’s for movies you know), etc. If you follow those rules, I once worked out that you’d have a 20% chance that you’d get a working phone number. The point is that keeping your random 10 digit phone number off the Internet offers you no additional security or privacy. Phone spammers can test call every possible North American telephone number just as hackers can scan every IP4 network address in the world (only 2^32 of those). Associating the phone number with your name is bad, I agree. That allows targeted attacks (and targeted spam calls). But you are not giving your name to this website operator. You’re giving him 10 digits — he could have pulled 10 digits out of thin air and it would likely have been someone’s phone number anyway.