I can't stand putting artificial sweetner in savory dishes like potato salad. I would also prefer using Dijon mustard and a bit more non-fat mayo instead of the fat-free yogurt. Then you won't need to add the artificial sweetner to counteract the sour from the yogurt. To the person who asked about the egg yolk: it's not raw yolk! The recipe is asking you to cut one of the boiled eggs open, pop out the yolk and mash the cooked egg yolk with the vinager to create the foundation for the sauce.