Well im also in a private exchange site I dont have any links available to give out right now though...

I think though some of the better ways to get more stumbles with the exchange is to click the users online one and stumble there site and when you leave me message state something like I stumbled your page please stumble mine back.

I do this becuase that way you know the user is active, instead of stumbling some random one that the user might no longer be using the exchange. and if you stumble someones they usuly stumble yours back