You're seriously asking people to put their passwords into a 3rd party website??

How many have done so, just out of interest?

This is not what's happening.

The UI may be a bit confusing. The verification to HN takes place w/o a password, but the site lets you create a separate password to protect access to the messages (once you're verified).

Quite a few have signed up so far...

Thank you for the clarification!