A personal knowledge database is a place where you not only write things down, but where everything you write may eventually become structured, linked and queryable data.
In SilverBullet your notes are kept as a Space (folder) of Markdown Pages on disk. As you write, SilverBullet continuously indexes your content — pages, links, tasks, list items and their attributes — into queryable Objects. You can then slice and reshape that data with Queries (SLIQ) and surface the results right inside your notes.
It is SilverBullet’s take on personal knowledge management (PKM). From Wikipedia:
Personal knowledge management (PKM) is a process of collecting information that a person uses to gather, classify, store, search, retrieve and share knowledge in their daily activities and the way in which these processes support work activities. It is a response to the idea that knowledge workers need to be responsible for their own growth and learning. It is a bottom-up approach to knowledge management.