Fakku in the words of their webmaster.
FAKKU (pronounced, faw-koo) is the largest English speaking hentai community in the world. The site launched on December 1st, 2006 and now attracts over 9 million unique visitors and over 1 billion pageviews a month, and those numbers continue to grow. FAKKU was created by Jacob Grady while he was a 19 year old college student studying marketing and web design in Massachusetts.
By far this one of the active group of scanalators and hentai or doujinshi galleries on the internet after the e-hentai gallery system. They have a large collection of hentai games, videos, pictures and manga and doujinshi and various languages. The forums are tightly integrated into their website you can see there is no need to register twice. The users are very active and you will get instant help!!