Gelbooru is a Japanese Hentai porn site. After exploring for some time, I sort of got the hang of it, but not so much. Actually, the better term for this site is a search engine. This is a Japanese Hentai search engine of some sort. The first page, or the home page, is just a plain white background, with a thick blue line in the middle of the page. On top of the girls, is a box where you can type anything and search for it.