Nick Kellet's presentation on Twitter for business emphasizes the evolution from passive consumption (Web 1.0) to active participation (Web 2.0), highlighting the interactive nature of social media. He discusses Twitter's role in real-time, hyper-local engagement, offering tips for effective usage, etiquette, and ways for businesses to connect with their audience. The session encourages attendees to embrace Twitter as a tool to share knowledge and build relationships while promoting local businesses.