Yup, that's the crux of it really. What we're doing now, or in blog comments, is having a conversation. We're allowed to "advertise" our business in offline conversation, so why not in online conversation?
The only substantive difference is that the online conversation hangs around, but if handled within guidelines, what's wrong with that? Indeed, done professionally it will enhance our reputation as the casual googler will likely find far more folk talking positively than negatively

