Okay, I promised I'd have word on this today, and here it is. Vanndril and I have conferred, and our decision is to allow doujins. But there are rules:
If a doujin/manga is longer than 5 pages in length, each page must be made into a child post of the cover image (or first page, if there is no cover). Because child posts do not show up in searches, the cover image (or first page) will have to be tagged with EVERY tag that is relevant to the manga. Bear in mind that you don't have to be super-detailed, but it helps. Also because child posts don't show up in searches, I don't see a need at this time to tag each individual page.
The reason for this decision is simple. We don't want to disallow doujins, because they're are great source of quality content. We don't want people to upload entire doujins normally, because that's spam-like and fills pages with what is essentially the same content (and also includes non-MC content).
For those who don't know how to make posts into child posts, here's how: Each post has an ID number. It's the first entry under the "Statistics" banner on the left side. When you click "Edit" on a post, you'll see a field labeled "Parent" (the 2nd field). To make a post into a child post, enter the ID number of the post you want to be the Parent into the "Parent" field. Click "Save Changes" and you're done. When you click on the parent post, there should be a banner above it indicating that it has child posts.
I would also recommend, if a doujin/manga has an E-Hentai gallery or similar, to put a link to it in the source field. Let's face it, our site is a little impractical for simply reading manga, especially those at particularly high resolutions. Still, some people may like the convenience of being able to download the full res manga without the need of a torrent.
I'm going to upload a doujin right now to demonstrate how it should look when it's done.