Didn't work in Firefox.
If you look at the page, though.. you can see exactly what they were doing:
Code:
var content = clipboardData.getData("Text");
if (content!=null) {
document.write(...)
Realistically, though, I think the risk is pretty low. So they've got your credit card number or something. Unless you give them enough information (like your WHOLE credit information, address, etc..) they just have a bunch of junk numbers or characters from everyone who connects to the website.