Why, exactly? I'm about 100x more likely to sign up for your site if you let me press a button and log in with my Google account. It's also really easy to implement with Django middleware.

Google turns up a Quora thing which, frankly, is full of handwaving bullshit.

Are there actual technical reasons why OpenID is bad?

I wasn't talking about whether I thought it was good or bad, just that it seems to me like most people on HN usually look down on it.

And the reasons are mostly ones of user-friendliness (not technical reasons). I've heard of plenty of people who still never signed up for StackOverflow because it requires OpenID.

As far as I understand it, OpenID is still used, for letting people login with Google or even Yahoo accounts, but no longer with full flexibility in OpenID providers.