i just increased the size of username in auth_user table to 100 and I
enter email as user name from my register user web page.

 Django auth is working fine. I use my own form and view but django's
authenticate and login methods.

It did not give me any errors saying I cannot enter or use (at) sign.

Am I missing something? Why are people writing alternate auth backends
for this?

Mind sharing your modifications?

-- Sent from my Palm Pre

i just increased the size of username in auth_user table to 100 and I
enter email as user name from my register user web page.

 Django auth is working fine. I use my own form and view but django's
authenticate and login methods.

It did not give me any errors saying I cannot enter or use (at) sign.

Am I missing something? Why are people writing alternate auth backends
for this?

Just for the record this is unsupported in Django (due to the constaints
django.contrib.auth.models.User.username), and I will guarantee this
behavior will break in the future  when model validation hits (currently a
GSOC project).

The reason e-mail isn't used as a username is due to, I assume, the way it
was initially created. There are a lot of sites that would prefer to have a
username instead of an e-mail available to the users. So a decision was made
a long time ago and released for us to use. And for me, and a lot of other
people who use Django, and even for your use case with the e-mail
authentication, it works well.

That said the custom auth backend and reading from a field named e-mail
directly, as I showed in the links, is really simple and the code is already
written for you. The only tricky part is creating a username, which you can
do by parsing the email address and placing it in the username field. Simple
really, only you need to know that is what is happening.

My recommendation is to extend the auth module a touch by adding less than
40 LOC to your code base. You could also rewrite the auth module if you
would like. I would not recommend relying on the undocumented behavior.

Michael