[caillou]

We considered many different authentications and chose Facebook and Twitter because they make it really easy to show avatars of the people who sign.

What alternatives would you suggest?

[marshray]

How about just asking for a name and email like everything else?

[aphyr]

Email address + gravatar.

[jefe78]

A simple registration form with some default avatars would be ideal, in my opinion.

[Seldaek]

Another factor was the really short time we had for development, so implementing those two allow us to cover the largest part of our target audience with a simple UI.

[meatsock]

fingerd