I might be biased because memorydial was complimentary to me ... but they SEEM like a human! Also I'm not all that opposed to robot participation in the scheme of things. Especially if they are nice to me or give good ideas :)
FWiW I mostly read HN at it's deadest time (I'm GMT+8 local time) and I see a lot of mechanical turk comments, especially from new (green coloured) accounts.
I always look for a response (eg: yours) before flagging them as spam bots . . .
