Typically talking to me about "portion control" makes me feel very cheated and melancholy, but I actually don't like a ton of dressing on my salads or oil in my stir fries. I also don't like trying to measure out a teaspoon of canola oil or tablespoon of balsamic for a recipe (i.e., my girlfriend bossing me around while she's cooking) and spilling it all over the place because the damn bottle pours too fast and the damn bowl is too far away. Yeah, that's mostly what I don't like.
This 17-ounce glass dispenser stores and measures out precise teaspoons, tablespoons, or milliliters of oil or vinegar for the health conscious eater and meticulous home cook. I guess you could use it for booze too, if you're particularly anal or stingy. Pretty cool how the dispensing works too: click the gray button beneath the bottle spout to suck liquid into its top holding chamber, and then pour just that amount out when you've got the right fill.