You can signup using the number of a public payphone if it makes you feel safer, with landline verification. (Of course, you expose yourself to having the accou

You can signup using the number of a public payphone if it makes you feel safer, with landline verification. (Of course, you expose yourself to having the account hijacked by anyone who figures it out and has acces to the payphone). But it won't improve your anonymity significantly, unless you also use it over TOR.