expand_patterns.js

// expand {{PATTERNS}}
// You can do this serverside. I just did it this way for demonstration purposes.
(function () {
	"use strict";

	var shares      = document.querySelectorAll("ul.share > li > a");
	var keywords    = document.querySelector('meta[name=keywords]').getAttribute("content");
	var description = document.querySelector('meta[name=description]').getAttribute("content");
	var params = {
		URL:      encodeURIComponent(document.querySelector('link[rel=canonical]').getAttribute("href")),
		TITLE:    encodeURIComponent(document.title),
		HASHTAG:  encodeURIComponent(keywords.split(",")[0]),
		TAGS:     encodeURIComponent(keywords),
		SUMMARY:  encodeURIComponent(description)
	};

	for (var i = 0; i < shares.length; ++ i) {
		var share = shares[i];
		var url = share.getAttribute("data-popup-url");
		share.setAttribute("href",expand(share.getAttribute("href"),params));
		if (url) {
			share.setAttribute("data-popup-url",expand(url,params));
		}
	}

	function expand (href,params) {
		return href.replace(/{{([^{}]+)}}/g, function (match, key) {
			return params.hasOwnProperty(key) ? params[key] : match;
		});
	}
})();

pinterest.html

<a href="javascript:void((function(d){var e=d.createElement('script');e.setAttribute('type','text/javascript');e.setAttribute('charset','UTF-8');e.setAttribute('src','//assets.pinterest.com/js/pinmarklet.js?r='+Math.random()*99999999);d.body.appendChild(e)})(document));">Pinterest</a>

popup.js

// Some services provide a share form that can conveniently be displayed in a popup.
// This event handler opens such a popup when attached to the click event of a share link:
function sharePopup (event) {
	"use strict";

	// only open popup when clicked with left mouse button
	// (middle click should still open the link in a new tab and
	// right click should still open the context menu)
	if ('buttons' in event) {
		if (!(event.buttons & 1)) {
			return true;
		}
	}
	else if (event.button !== 0) {
		return true;
	}

	// gather popup parameters
	var href = this.getAttribute("data-popup-url") || this.href;
	var params = {
		menubar:   "no",
		location:  "no",
		toolbar:   "no",
		status:    "no",
		resizable: "yes",
		width:     "640",
		height:    "480"
	};

	for (var name in params) {
		var value = this.getAttribute("data-popup-"+name);
		if (value) {
			params[name] = value;
		}
	}

	// center popup window
	var width  = parseInt(params.width,10);
	var height = parseInt(params.height,10);

	params.top  = Math.max(0, Math.round((screen.height - height) * 0.5));
	params.left = Math.max(0, Math.round((screen.width  - width) * 0.5));

	var spec = [];
	for (var name in params) {
		spec.push(name+"="+params[name]);
	}

	// open window
	window.open(href,'_blank',spec.join(","));

	// prevent navigation to the share form
	if ('preventDefault' in event) {
		event.preventDefault();
	}
	else {
		event.returnValue = false;
	}
	
	return false;
}

share.html

<p>Share on:</p>
<ul class="share">

	<li><a target="_blank"
		href="https://alpha.app.net/intent/post/?url={{URL}}&amp;text={{TITLE}}"
		data-popup-width="640" data-popup-height="400"
		onclick="return sharePopup.call(this,event);">App.net</a></li>

	<li><a target="_blank"
		href="https://www.blogger.com/blog_this.pyra?u={{URL}}&amp;n={{TITLE}}">Blogger</a></li>

	<li><a target="_blank"
		href="http://delicious.com/save?v=5&amp;url={{URL}}&amp;title={{TITLE}}"
		data-popup-url="http://delicious.com/save?v=5&amp;url={{URL}}&amp;title={{TITLE}}&amp;noui&amp;jump=close"
		data-popup-width="555" data-popup-height="555"
		onclick="return sharePopup.call(this,event);">Delicious</a></li>

	<li><a target="_blank"
		href="http://digg.com/submit?url={{URL}}&amp;title={{TITLE}}&amp;bodytext={{SUMMARY}}">Digg</a></li>

	<li><a target="_blank"
		href="https://www.facebook.com/sharer.php?u={{URL}}&amp;t={{TITLE}}"
		data-popup-width="626" data-popup-height="436"
		onclick="return sharePopup.call(this,event);">Facebook</a></li>

	<li><a target="_blank"
		href="https://plus.google.com/share?url={{URL}}"
		data-popup-width="600" data-popup-height="460"
		onclick="return sharePopup.call(this,event);">Goolge+</a></li>

	<li><a target="_blank"
		href="http://www.linkedin.com/shareArticle?mini=true&amp;url={{URL}}&amp;title={{TITLE}}&amp;summary={{SUMMARY}}"
		data-popup-width="520" data-popup-height="570"
		onclick="return sharePopup.call(this,event);">LinkedIn</a></li>

	<li><a target="_blank"
		href="https://myspace.com/post?u={{URL}}&amp;t={{TITLE}}"
		data-popup-width="880" data-popup-height="500"
		onclick="return sharePopup.call(this,event);">MySpace</a></li>

	<li><a target="_blank"
		href="http://www.reddit.com/submit?url={{URL}}&amp;title={{TITLE}}">reddit</a></li>

	<li><a target="_blank"
		href="https://www.stumbleupon.com/submit?url={{URL}}&amp;title={{TITLE}}">StumbleUpon</a></li>

	<li><a target="_blank"
		href="https://www.tumblr.com/share/link?url={{URL}}&amp;name={{TITLE}}&amp;description={{SUMMARY}}"
		data-popup-width="446" data-popup-height="430"
		onclick="return sharePopup.call(this,event);">Tumblr</a></li>

	<li><a target="_blank"
		href="https://twitter.com/share?url={{URL}}&amp;text={{TITLE}}&amp;hashtags={{HASHTAG}}"
		data-popup-width="640" data-popup-height="400"
		onclick="return sharePopup.call(this,event);">Twitter</a></li>	

</ul>