A nice definition for Digital Gardens from author Anne-Laure Le Cunff from Ness Labs:

A digital garden is an online space at the intersection of a notebook and a blog, where digital gardeners share seeds of thoughts to be cultivated in public. Contrary to a blog, where articles and essays have a publication date and start decaying as soon as they are published, a digital garden is evergreen: digital gardeners keep on editing and refining their notes.