Because if you already have a username, this guy's waiting for you.

Let's say I already have a username.

Subscribers will have a username and password for their Irish Times subscription account, and can sign in on desktop, tablet or smartphone.

'The Valve PDC had a username "build" with a blank password,' he explains.

Oracle said none of the bugs it is fixing next week can be exploited remotely without having a username and password for the database server.