The way I see it is that you create the context yourself. You create a pool and only share the URL with people in a known context (such as your colleagues at work). That way you all get to discover where you are in the spread of your team, but without knowing which salary is tied to which individual.

Obviously, how you structure the context defines what it means to you. If you share it with everyone from managers to newbie graduates your context will be different than if you just share it with people you consider to be at the same level as you.