text: what happens if u register same username in yahoo from 2 diff countries at the same time? how does yahoo databases in different parts synchronises them at same time. it takes atleast a sec to synchronise between all databases, right? does that mean u can register same username from 2 diff countries if u do that simultaneously they could have run into this problem in the olden days, then they were just giving my-id@yahoo.com type of ids. now based on the country we select, they have started giving country specific mail ids. so for some one in india, it would be my-id@yahoo.co.in and my-id@yahoo.co.de for germany and so on. this would reduce the duplicate ids problem.