Post Formats is a theme feature introduced with Version 3.1. Post Formats can be used by a theme to customize its presentation of a post.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus – more on WordPress.org: Post Formats