Here's how it works: you use PopVox to communicate with Congress, sending support or oppose messages which are publicly tallied so all can see which way any given Congresscritter's distric was leaning. This tool then shows you, bill by bill, whether your two senators and congressperson voted the way you told them to through PopVox.
If you contact them some other way, PopVox can't possibly know that (nor can anyone but your congresscritter, so there's no accountability), so it's useless without an account.
To accomplish the goal of knowing how my congresscritter (really?) matches with me, I should not need an account. If I wanted you to contact them for me then OK but to call the site useless without an account just makes it so.
disclaimer, I wrote up a site like this, but haven't coded/launched because success is dependent on design skills and the ability to implement them, not in quality/quantity of info. Until ordinary citizens are using it, no rep is going to pay for it as a platform for access, and it needs really great design to get ordinary people to use it. If I become rich this is the first site I'm going to throw money at because I think we really need something like this.
(You can embed them in your personal homepage too. It's free. I've got an anti-SOPA one on my homepage.)
