That post explains mixing ethanol and water to produce vodka creates a more dense liquid. Now I've taken it a step further, because what most people do when they drink vodka is dilute it into some sort of water-based beverage. They might be diluting it with apple juice to take shots, for instance. In that case they might start by half-filling the shot glass with vodka, and then adding the juice until it is full. They believe they are adding as much juice as vodka, but they're not. All things equal, if they originally filled the glass to exactly half way with vodka and then used condensed apple juice to fill the rest of the glass, then in their shot glass is more than half a shot glass of apple juice.
If you poured equal portions of vodka and water, 500ml each into a container you would have 941ml of fluid in that container.