Twitter Card Support in Nikola
What are Twitter Cards? Did you notice that for some sites, when you click on tweets that have links, you get a small preview of the content? Well, that's a twitter card.
This still needs a little improvement to support the richer "media" cards, but it does work:
You don't have to do anything in your site, but setting the "description" metadata to your posts helps make this more accurate (and it also works for google+)