A policy is a rule or guide on how to handle various situations. In your Joomla! site and your company, you probably have policies on how to take customer orders, for instance. Your company will follow a prescribed method for receiving the order, receiving the money, and fulfilling the order. If your company doesn't follow this method, then you probably have not been in business long (and probably won't be much longer). You need to follow a standardized methodology to fulfill customer orders, to give customer support, and so on.

Developing your incident response policy is the same exercise. Your plan should take into consideration remote teams (again, your host). If an incident occurs that results in an outage, then your response should be to contact the host, establish the true nature of the outage, and ensure that they take appropriate steps. But it doesn't end there. After the site is operational again, you should be prepared to "close" the incident...