I noticed this morning that the "Reply to" button does not show unless you are logged in. The "Reply to with quote" does.
That's because guests aren't allowed to post. You'll have no posting options if you're not logged in.
Thanks for noticing we just upgraded the site though! Please let us know if you notice anything else out of the ordinary. It's likely that button was there before and would generate an error "not logged in" if you clicked it. Now it's just suppressed.