Sounds great, looks great, but actually trying to sign up with a new account using email address (because using my Twitter or Facebook login on this seems well, kind of inappropriate) returns "Internal Server Error".
We're aware of the email issue, and we're working to fix it. Please keep in mind that this is an alpha release from a small team in a little under two weeks, and there's a long way to go.
And actually - this is because our Heroku sendgrid add-on ran out of emails so....herp derp. It's being taken care of; I'm not sure anyone imagined as much attention as it's gotten today.
As much as I'm sympathetic to a small team getting a spike in traffic, I stand by that comment... It's a pretty big "fail" when a huge rush of users trying to register results in... nobody being able to register. At the very least they could have been capturing the emails for later follow-up. How many of those people will remember to come back later and sign up again?
Fail.