This plugin adds the "news_keywords" meta tag so, Google News can index your site better.
If you are using WordPress to power a news site, you might be interested in helping Google News to find and classify your content. Google introduced a new meta tag to their crawlers some time ago, which is doing exactly this.
The element with the name "news_keywords" is supposed to describe your content very briefly. You can read more on this topic over at Google: http://support.google.com/news/publisher/bin/answer.py?answer=68297
This plugin adds the meta tag and outputs the article keywords into it.