Metatags, sharing, and social media | Technology for Marketers

Here's a great guide to tagging your content to optimize presentation on FB, LinkedIn and Twitter:
"As social media platforms continue to become a dominant traffic source for your content, it becomes even more important to put in the small amount of additional effort to ensure your story can connect with each audience. Through the proper use of metadata, you can easily achieve this goal with your existing content as well as make this a part of your editorial process moving forward."

Bonus: this is quite easy with Drupal and the Metatag module.