In:

http://psf.upfronthosting.co.za/roundup/meta/issue555

the user reports the following steps:

  user registers
  gets an email sent to them to confirm the registration
  click on link
  gets back message 'node with key "username" exists'

Need a couple of things:

1) verify username is available before sending registration
   (possibly as an option since this could be used to fish for
   usernames)
2) Change the error message to 'User "username" already exists.'