The only way to avoid it is to have an invite-only site where new invites are interviewed and voted on by a committee/small group of members. The problem is th

The only way to avoid it is to have an invite-only site where new invites are interviewed and voted on by a committee/small group of members. The problem is that as a site gets bigger, more and more people join that have views that are opposed to the original intentions of the site (and owners) and the site degrades over time. The other problem is that you don't know the age of the person posting. Reddit is now filled with high school/younger kids posting. It parallels a true democracy. If we had a true democracy, eventually the extremes would rule.