Great post so far, and helpful as well. I do have one point I would like to make coming from a privileged point of view. As Jen mentioned, when you are first are introduced to it in a personal sense, it is unsettling, uncomfortable and can even make you angry or very upset. I stumbled into this myself on FtB, where I jumped into a conversation without really considering how different a situation is for people who are not in my group. Well, I should correct myself, I did consider it, but I simply don't have the knowledge to draw on to do so in any meaningful way. Not knowing the frequency of trolling on such topics, the nature or perceived tone of some of the responses to me seemed overly hostile(at worst) and unwelcoming(at best). I went back and forth a bit, almost everything I said made it worse, except that I did express why the issue(s) in question were important to me and some people accepted that I was not a troll and not trying to derail the thread. In doing so, they pointed me towards some of the Crommunist's posts, which I found very helpful.
Anyhow, the point I am trying to get to is this. The first time a person is exposed to the notion of being privileged, it is most often not pleasant, and they will probably get defensive/angry about it. It is important to not introduce them to it in a way that makes it more unpleasant. Please, please do not make this out as me trying to blame the underprivileged for the problem. But I imagine part of the point here is trying to spread the word, and that is going to include reaching out to a lot of people who are privileged in one area or another. Most of the work/effort to understand privilege is going to be on them, say its 90%/10% on the person of privilege, we still need to get as close to that 10% as possible. After all, we want people to stay, and contribute.
Saying things like "check your privilege" or "Your privilege is showing" is probably not the best thing to say to someone with a low post count, as they may not be familiar with the concept, or at least in regards to themselves. People who somehow find there way to this site and are atheists are probably not going to take the time to read intro material, (unless you force them somehow) they are far more likely to jump right in.
I think a good example of this is from the Dogs and Lizards post:
When she says “you don’t have to put up with being leered at,” what she means is, “you don’t ever have to be wary of sexual interest.”
Helping to break down exactly what the issue is helps to pinpoint what is meant by privilege, and why the person needs to be aware of it. Describing things that happen, without explaining why it is harmful to you makes it harder for someone who is not part of your group to understand what it is you are getting at, or why it is a problem at all. Without this understanding, things can decend into extremely unhelpful bickering, where there is no progress made. Potential allies can become enemies(NOTE: I am not blaming anyone here for this), most often due to their own inexperience and probably youth. I doubt much/most of the pushback against A+ is from actual overt racists, homophobes etc.. Are there a few? Probably. But for the most part, I doubt it. They feel attacked for being White, Male, and strait (or what ever group they are actually a part of). However silly or irrelevant you might think that is, most of these people probably agree with you on most things, yet now your are both at odds. I think too large a portion of white male strait athiests are being "turned off" from FtB and A+, I don't think it really has anything to do with Feminism, but has everything to do with privilege and the communication gap that exists there. People are stubborn, and once turned off, might not come back, when they feel insulted, might insult you back, etc...
I have more to say on the subject, but I think it serves the discussion better to do it one part at a time. Should this perhaps be a separate subject, I don't want to derail this one, perhaps "Communicating with people of privilege"?
I don't know that I communicated this in the best way possible, so if it seems hostile, it is not meant to be.