gistfile1.js

// ==UserScript==
// @include http://www.delicious.com/network/*
// ==/UserScript==

(function() {
	var style = document.createElement("style");
	document.getElementsByTagName("head")[0].appendChild(style);
	var sheet = style.sheet;
		sheet.insertRule("li.post a:visited { font-weight: 800 }", sheet.cssRules.length);

	var posts = document.querySelectorAll("li.post");
	for(var i = posts.length; i;) {
		var post = posts[--i]
		var postlink = post.querySelector("a.taggedlink")
		if(window.getComputedStyle(postlink, "").fontWeight == 800) {
			post.style.display = "none";
		}
	}
})();