It generates an archives page and RSS feed. It also has a couple useful scripts for publishing to gh-pages and watching for changes. So it's "batteries includes".
git clone https://github.com/sole/metalsmith-blog-example.git
Then you can edit away!
In theory Metalsmith can be used to build anything, as it's just "an static file generator". But it can suffer a bit of the usual node.js "module decision paralysis", and documentation quality varies a lot between different modules.
So here's a complete working example. Enjoy!