Post Formats will become the norm for publishing content with WordPress. Behind the scenes since WordPress 3.1, 3.6 will put Post Formats in the spotlight.
In short, Post Formats are used to structure articles based on their content type. Video Post Formats should highlight videos over anything else. Quote Post Formats should focus on quotes. It’s pretty self-explanatory.
Theme developers will handle how this content is structured and displayed. This is an opportunity to get creative and make publishing content fun for the user.
As of now, Standard, Image, Gallery, Link, Video, Audio, Chat, Status, Quote, and Aside will be supported. Read the Post Format descriptions.
The Volatyl Framework will support all Post Formats. They’re already being implemented. Right now, you’re reading an Aside disguised as a “Quick Snippet.”
Edit: The WordPress crew decided to leave Post Formats in the background for the 3.6 release. Smart move. Volatyl will not support Post Formats in the core (reserved for child themes) until they become default WordPress functionality.