Some of you know (and use) the website I created a year ago, Scirate.com, a place where arXiv papers can be voted for digg style and comments can be left on the papers. After a while of not tinkering much with the website I'm beginning to add more features that I've been thinking about for a while now. The first feature is just a small one: the ability for the website to send trackbacks to the arXiv when someone comments on a paper. After some false starts I think I've got this feature up and running, and indeed the first trackback now appears for arXiv:0802.3351.
Now, of course, the bigger question is how to get more participation for the website from the more scientists (not everyone is as ungrumpy as the quantum computing community, it seems.)
Dave, I think you should put this out on the street corners in downtown, so to speak: I didn't know about the site but I think it is a great idea.
Take a leaf out of quantalk's book. Get a research grant and start paying people $100 to leave comments on the site. Mind you, we don't know if that strategy actually works yet.