I'd never heard of this before, but I did find other studies to back it up. This study from 2005 found that vinegar (and peanuts, if you're interested) decreases glycemic load (i.e. it slows down the entry of glucose into your system). This other 2005 study replicated these findings, and found that vinegar also increases feelings of fullness.This study from 2009 supports both of these findings (along with similar effects for cinnamon). An older study links these effects of vinegar to delayed gastric emptying (i.e. food sits around in your stomach for longer).
So, it sounds like vinegar supports weight loss by keeping you full for longer. Because it lowers glycemic load, it can probably also help decrease risk for obesity-related disease like diabetes and heart disease.