I sat down for a few minutes today and setup replying by email for the site.
Now when you get an email notification from the forum, at the bottom of the email will be a small blurb of text that will say:
To respond, reply to this email or visit Welcome to PIXLS.US Discussion in your browser.
This means that you can now either come to the forum here to craft your reply, or you can simply reply to the email notification that was sent to you. Neat!