Andrew Nacin, WordPress core commiter, explains post formats in his blog. Very interesting reading for WordPress theme developers.
Just in time for thanksgiving, WordPress makes version 3.1 available for download. The new version has some awesome enhancements such as Post Formats, a new dialog for link creation, Admin Bar, faster password reset, multi-taxonomy queries in the core and index pages for custom post types.
Mark Jaquith clarifies the difference between Post Formats vs. Custom Post Types.
Post Formats are (…) a taxonomy convention with a UI wrapper. So if you have “Asides” on one theme, you can transport them to another theme. If people create their own formats, their portability will be zero (…)
Nacin posted a tentative list of post formats to be included in WP 3.1. Post formats will be meta information used by theme to customize presentation.