Ideas We Want and Ideas We Don't

The point of this project is to open the floodgates of public discourse. That said, it is of the utmost importance that the discourse remain civil so that the forum can remain free and open. We will rely on our own community administration and reports of abuse from our users to monitor the site.
But we also want you to be respectful. So what's a good rule of thumb? If you couldn't say it in a college classroom, you probably shouldn't say it here.
How will bigthink.com judge what crosses the line? In the words of Supreme Court Justice Potter Stewart, "We'll know it when we see it."