[czr80]

From the trades that don't happen because the producer can't sell to certain segments at a lower price (for fear of reducing his profit on other segments). I suppose it's worth noting that this isn't an issue in perfectly competitive markets (since there price = marginal cost). But, outside econ-101, there aren't really many perfectly competitive markets.

By the way, as I mentioned in my first post, I definitely agree this is about capturing consumer surplus too.