Both things I'm citing can work on a large scale with some effort, through the power of mass-deletion and auto-replying. I'm just not seeing how pushing some text towards a government representative compels them to act at all, especially when money and power are what's on the other end of the scale.
Well, maybe take a look at how this worked out? Because you're saying that all they have to do is delete the emails, but clearly that isn't what happened here.
The biggest difference is that there's little effort involved here. One click to send mass emails out to all relevant politicians. No they can not ignore a constant stream of emails from the electorate. Frankly, it doesn't seem like you understand why this site was different or effective.