Danbooru: content and format
Running since 2005 at danbooru.donmai.us, it functions less like a gallery and more like a crowd-maintained reference library: millions of images across fan art, original illustration, doujinshi, and official art, each post filed under a web of interlinked tags.
Finding your way around
Tag namespaces separate characters, copyright series, artists, and general concepts, while metatags such as rating: cut results along a four-tier scale — general, sensitive, questionable, explicit — so a single search syntax surfaces everything from clean wallpapers to explicitly adult artwork. The official_art tag alone counts more than half a million posts. Around the core sit the systems that keep the pile navigable: wiki pages documenting tags and series conventions, pools chaining related images into sequences, notes pinning text annotations onto individual pictures, plus comments, favorites, and a forum.
The practical picture
Browsing is free and starts filtered: logged-out visitors carry a default blacklist that hides guro, scat, furry, and anything not rated general. Reaching the questionable-to-explicit side means registering a free account and trimming that blacklist; members also upload, comment, vote, and keep favorites under the site's documented upload and community rules.
