Thanks for the kind words. I've focused a good deal in the past few years on teaching/communication (see my profile for a link to some of my basic-physics lectures for student taking the MCAT), and I'm very grateful for the opportunity to discuss our work with this community. Thanks for your interest and great questions!

Actually, HN does do /almost/ private messages, if you hellban your account, and the recipient of your reply comment has “show dead” turned on.

(of course, anybody can activate the “show dead” option, but, in reality, there’s no such thing as privacy on a web server, since there’s always a system administrator noticing unhashed passwords scroll through the log stream)