Sooner or later you make a mistake with the community. If not you’re not pushing the envelope, is my experience. Shel Holtz has a very good Crisis Communication primer.

Notable:

When responding to a crisis, you should…

• Respond quickly, accurately, professionally and with great care
• Treat perceptions as fact
• Acknowledge mistakes (today, we’d say, “Be transparent”)
• Tailor messages to address the aggrieved or angry party
• Note the other side’s concerns; don’t be dismissive
• Make no public confrontations
• Emphasize the existing relationships in which you have built
  capital; they are more credible during a crisis than your own
  spokespersons

Good piece, recommended reading.