A digital garden is a decentrally and non-chronoligically organized collection of evolving ideas. They're meant to be continuously revisited and explored and expanded. Like a physical garden, it is meant to be nurtured. To faciliate this process, the notes are linked through contextual associations. Wikipedia in this sense can be considered a giant digital garden nurtured by millions of people.
Some examples of personal digital gardening tools (non-exhaustive):
Instead of seeing a personal website as a filtered representation of self in the digital space, a digital gardeer sees it as a mere reflection of their actual self, who are also always thinking, always associating, and always growing. It is the rejection of the perfect self and the courageous embracement of eternal imperfection.