Not a gray area? The Reddit admins say otherwise, and presumably they would know what they've been dealing with:

> Beyond these clear cut cases, there is a huge area of legally grey content, and our previous policy to deal with it on a case by case basis has become unsustainable. We have changed our policy because interpreting the vague and debated legal guidelines on a case by case basis has become a massive distraction and risks reddit being pulled in to legal quagmire.

While we're at it, Neil Gaiman points out examples of several of those gray areas:

http://journal.neilgaiman.com/2008/12/why-defend-freedom-of-...