If you ever faced flame wars on your orkut community, Google developed a new feature that lets community owners access to a new setting: "only owner and moderators can create forum topics," which they can turn on and off as they wish. To try, just go to "edit profile" page of your community. When passions run high, you can now make use of this feature within your community. You can also try creating a few new forum topics like "Rant Room" or "Suggest new forum topics," where community members can continue their discussions without affecting everyone else's experience.
More info: orkut blog