Viral advertising is a marketing strategy that utilizes social media and other online platforms to spread a message or promote a product or service through the rapid sharing and circulation of content by individuals. This type of advertising relies on the power of word-of-mouth and the contagious nature of online content to reach a large audience in a short period of time. It often involves creating unique and attention-grabbing content that encourages people to share it with their networks, resulting in a viral effect that can greatly increase brand awareness and engagement.