Making a "partly private forum."

[Dorign]

I am wanting to make an adult forum. By adult, I don't mean pornography, but as we all know, hilarious images are on the internet and from time to time they contain nudity. My last forum I ended up letting shut down because I was tired of moderating, so this time I'm planning on running a forum that is, for the most part, "no holds barred" (except for blatant pornography).

I would like the forum to be private, for the most part, so that I will require users to be logged in and require users be 18 or older to join, just to reduce hastle on my part.

My problem is, shutting a forum down to "only registered users" can make it hard to get new users who join because they read funny posts, or see something they want to reply to. I was wondering if any of you could tell me the best way to keep the forum private and "safe for work" for non-registered members, but still readable.

I was thinking maybe images won't show up to people who aren't logged in, and words would only be censored when a user wasn't logged in.

Is something of this magnitude possible? Does it already exist? Maybe the vB 3.6.8 can do this "out of the box"?

Thanks!