someone has set us up the bomb

a new hack is going around that checks what sites you've been too. guess how? the script has a little database of sites and it just checks whether the link is the changed color of when it has been visited

 var link = document.createElement("a");
 link.id = "id" + i;
 link.href = websites[i];
 link.innerHTML = websites[i];

 document.body.appendChild(link);
 var color = document.defaultView.getComputedStyle(link,null).getPropertyValue("color");
 document.body.removeChild(link);
 
 if (color == "rgb(255, 0, 0)") // the site has been visited :)

demo - http://ha.ckers.org/weird/CSS-history-hack.html