data/pages - contains your current pages
data/meta - contains meta information about your pages (like who created it originally, who subscribed to it, …)
data/media - contains your current media (images, PDFs, …)
data/media_meta - meta data for the media
data/attic - all the old versions of your pages
data/media_attic - all the old versions of your media
conf - the configuration settings
can exclude these directories: cache, index, locks, and tmp