Twitter Stopped Letting New Users Pick Their Usernames During Sign-Up Years Ago
daringfireball.net
daringfireball.net
This is a problem Twitch runs into, there are many more people watching than streaming but everyone has an account name and can stream so a lot of names are taken.
At the time you had to pay to change your gamertag so when we introduced this you got a free change after it had generated one instead.