This FAQ will show you how to quickly add OG or Open Graph data to your Magento product pages. It involves editing just one of  your template files.

1. Go to app/design/frontend/default/YOURTHEME/template/page/html/head.phtml
2. Add this code snippet below into this file. This code can go anywhere in the file but we usually put it before Magento outputs the theme CSS files, so before this line <?php echo $this->getCssJsHtml() ?>

<?php /* Open Graph Protocol for Facebook and SEO START */ ?> <?php if(Mage::registry(‘current_product’)): ?> <?php $product = Mage::registry(‘current_product’); ?> <meta property=”og:title” content=”<?php echo ($product->getName()); ?>” /> <meta property=”og:type” content=”product” /> <meta property=”og:image” content=”<?php echo $this->helper(‘catalog/image’)->init($product, ‘small_image’)->resize(200,200);?>” /> <meta property=”og:url” content=”<?php echo Mage::registry(‘product’)->getProductUrl(); ?>” /> <meta property=”og:description” content=”<?php echo strip_tags(($product->getShortDescription())); ?>” /> <meta property=”og:site_name” content=”<?php echo Mage::app()->getStore()->getName(); ?>” /> <?php elseif(Mage::registry(‘current_category’)): ?> <meta property=”og:title” content=”<?php echo $this->getTitle() ?>” /> <meta property=”og:type” content=”product.group” /> <meta property=”og:url” content=”<?php echo $this->helper(‘core/url’)->getCurrentUrl();?>” /> <meta property=”og:description” content=”<?php echo strip_tags($this->getDescription()) ?>” /> <meta property=”og:site_name” content=”<?php echo Mage::app()->getStore()->getName(); ?>” /> <?php elseif((Mage::getSingleton(‘cms/page’)->getIdentifier() == ‘home’ && Mage::app()->getFrontController()->getRequest()->getRouteName() == ‘cms’)) : ?> <meta property=”og:title” content=”<?php echo $this->getTitle() ?>” /> <meta property=”og:type” content=”website” /> <meta property=”og:url” content=”<?php echo $this->helper(‘core/url’)->getCurrentUrl();?>” /> <meta property=”og:description” content=”<?php echo strip_tags($this->getDescription()) ?>” /> <meta property=”og:site_name” content=”<?php echo Mage::app()->getStore()->getName(); ?>” /> <?php else: ?> <meta property=”og:title” content=”<?php echo $this->getTitle() ?>” /> <meta property=”og:type” content=”article” /> <meta property=”og:url” content=”<?php echo $this->helper(‘core/url’)->getCurrentUrl();?>” /> <meta property=”og:description” content=”<?php echo strip_tags($this->getDescription()) ?>” /> <meta property=”og:site_name” content=”<?php echo Mage::app()->getStore()->getName(); ?>” /> <?php endif; ?> <?php /* Open Graph Protocol for Facebook and SEO END */ ?>

Thanks to the guys over at Nailed It Design for this FAQ.