• An example sentence—even if we’ve only found one sentence for a word, we’ll show it to you. (And we’ll show you where the sentence came from, too!
• Related words: not just synonyms and antonyms, but words that are used in the same contexts. (For instance,cheeseburger, milkshake, and doughnut are not synonyms, but they show up in the same kinds of sentences.)
• Images tagged by our friends at Flickr: want to know what a “pout” looks like? We’ll show you.
• Statistics: how rare is “tintinnabulation”? Well, we think you’ll see it only about once a year. “Smile”? You might see that word many times, every day.
• An audio pronunciation—and you can record your own!
• Something YOU tell us! Use the “Contribute” links to tell us something—anything—about a word.

There’s Twitter element too! It show how a word is really used.

This idea came from Erin McKean at TEDTalk 2007.

[Wordnik]