Well, I'm definitely open to hear some guideline suggestions, but the current site attitude (not a formal policy) is that assets intended to provoke or arouse (a.k.a. "lewd") are not really what this site caters to. We do have some things like nude 3D models, but their intent is not for lewdness. Those submissions are primarily for anatomical reference and model bases. 

Although OGA doesn't claim to be a 100% SFW site, we do try to keep things as SFW as possible. The controversy you reference was a whole different level. That was controversial primarily because it was associated with, and pushing the borders of, pornographic content featuring characters of questionable age. Was the content itself porn? Some would debate it. The associations and links that came with it were definitely trouble, though. As one of the other admins put it, "If it's remotely sexual and it involves drawn or 3D children, it definitely does not belong here." We won't be allowing that on OGA.

The site's founder, Bart, generally keeps a philosophy of not defining every minute policy with a formal rule, instead allowing situations to be judged on a case-by-case basis. I understand this may be frustrating since it doesn't give clear guidelines on what is and is not allowed, but that is probably intentional. This topic has no clearly defined line where one thing is fine and on the other side of the line it's outlawed. As a soft rule, though, I would reiterate that OGA's audience is generally not seeking lewd assets.

As for your involvement in that controversy, titleknown, don't worry about it. You were nither the submitter nor the protester of the content in question.

Grapple Girl

https://opengameart.org/content/tetine-elfe

https://vimeo.com/21122663

So, I think part of this is going to come down to what the laws are.  Over at the RPG Maker forums, which I moderate for, they have to keep things at PG-13 because they're a business, and there are some very specific laws about distributing things of a pornographic nature.  I do know that these laws aren't as big of a deal for privately run sites, like this one is, but I think there's an element of what amount of risk Bart wants to take, since I'm pretty sure he'd be liable if something went south.

Everything here is pretty PG-13 right now and I prefer it that way.  It makes things useable for the widest range of people.  If we start catering to those who want to post things of a more extreeme nature, we're going to be turning off some of the people who like to come here with a more conservative preference.  Maybe it would draw in more people who are interested in that sort of thing, but that would change the nature of the site.  I'm not for it.  I would feel the need to quit following the site to limit my own exposure.

I'm open to hearing other sides of the issue though, I'd love to know what your guidelines would be.  Maybe it could be done in a way where we wouldn't be alienating anyone.

I agree with Sharm. I think it would completely change the nature of OGA.

And if the site did cater to this, it should have the option to filter out explicit material. That is probably a given.

I honestly don't want anything explicit on the site. I definitely wouldn't be showing the site to my young neices & nephews for the risk of running across something. No filtering system is perfect. We would be dependent on submitters marking explicit submissions as such. Else we would have to start screening submissions. And I think OGA already might have more workload than it has resources. Allowing such material will put a larger burden on the administrators.

titleknown outlined some reasonable guidelines for lewd assets (probably not showing up here because of the nature of the topic and the spam filter hitting on all the terms that are very common to porn site spam, unfortunately)

...but I think the need for so many new guidelines really underlines the need for such assets to be on a separate domain or sub-site. A very effective filter would certainly be necessary before such assets could be hosted on OGA, but- As Antum pointed out- no filter is perfect. I don't have the access to implement something like that, anyway. I'm more of a moderator than a server administrator.

I can definitely see a gap. There isn't really a niche for free and open source art, focused on games, of a lewd or "beyond PG-13" nature. It looks like it would actually be faster to have such a niche on a separate site than to incorporate all the things needed to blend it with this one.

If it were to be on a sub-site, I suppose it could access the main OGA database so that users can search through the "non-lewd" art as well without changing sites. Ya?

Lewd & indecent! Lol!

I'm sure there's no problem with submitting an anatomically correct tasteful full frontal nudity man or woman here.  Tetine Elfe and Grapple Girl are fine.  I'm sure even a topless over-endowed succubus and harpy are fine given the classical archetypical exemptions. I don't see a prude panic here.

The problem however was someone suddenly uploading sexually charged "shotacon" artwork which has huge legal issues in many countries (as well as being artistically derivative of a certain well-known shota artist so there's some derivative baggage on top of the existing legal issues).  A sexualized underdeveloped character should raise a red flag in any international art community with some non-perverted common-sense.