You can add pictures that they offer, links to related information and a link at the bottom of your post to related stories. And the gadget does all the work for you, adding things in a sidebar next to your create post editor as you type. It finds items related to what you are typing about and lets you choose which ones to use in your post.
You can read all about Zemanta here and see it in action on my post here. If you write an entertainment blog, a news blog or a current events blog, this would be the perfect gadget for you!