The true lowest common denominator doesn't come from pandering to people's love for profanity, toilet humor and breasts. Obviously, since some people are offended by these things, it's not common. No, the real lowest common denominator comes when people try to avoid offending anyone. Think about elevator music - everyone slightly dislikes it, but companies can't pick anything better because that choice might offend someone more than elevator music, and it doesn't bother people too much. The soft jazz played in dental offices is another example. Political correctness often results in this, as any slightly risque jokes might offend, heaven forbid.

This is death by blandness.