A formal letter with a professional tone, addressed to 'Mr. Billy Kay', discussing the company's marketing strategy and the importance of social media engagement. The letter highlights the need for a comprehensive approach to digital marketing, including the use of social media platforms, content marketing, and email marketing. It also emphasizes the importance of measuring the success of these efforts and adjusting the strategy accordingly. The letter is written in a clear and concise manner, with bullet points and numbered lists to emphasize key points.