In the context of Site Reliability Engineering practices, especially during a large, ongoing incident affecting customer-facing applications, effective communication is crucial. The best approach is to ensure that all stakeholders, both internal and external, are kept informed in a timely manner. This involves providing periodic updates to all stakeholders and committing to a 'next update' time in all communications. This approach ensures transparency and manages expectations effectively. Delegating communication tasks or focusing solely on one group of stakeholders (either internal or external) is not as effective as ensuring all parties are informed. Therefore, the most efficient and inclusive strategy is to provide updates to all stakeholders periodically and commit to a 'next update' time in all communications.