** As a product marketer at Zapier, I'm passionate about helping customers reach more people who could benefit from our product. To do this, we need to deeply understand the needs of different people and how we can teach them about it. Defining your market is crucial in creating products that resonate with specific audiences, and it involves understanding the total addressable market (TAM), which translates to "total addressable market." TAM helps us understand how many people could benefit from using our product or service, along with the revenue opportunity of getting those people to use and succeed with our business. By establishing your TAM, you can get a broad idea of the groups that you're trying to reach with your marketing efforts and build your business for. To find your TAM, you'll need to start with a general understanding of what qualities your target customer might have, consider demographic questions, look for publicly available data, factor in repeat purchases and risks to your market share, and err towards conservative estimates. Once you have your total addressable market, you can slice it into specific slices using market segmentation, which involves identifying the size and nature of opportunities for your business in the market. Market segments are groups of people built around shared demographics, psychographics, firmographics, purchase behaviors, preferences, awareness, or any other factor that makes sense for your audience. By identifying core market segments that can largely meet your product where it is today, you'll want to target them first, as they'll help you build momentum and capital to reach growth market segments. Market segmentation is part science and art, requiring a deep understanding of your customers' characteristics, quantitative analysis, and specialized statistics know-how. Marketing personas enrich segments by humanizing each segment with a story arc and backstory, helping you understand the wants and needs of your segments on a deeper level and revealing things like experiences, goals, and motivations. While marketing personas should be used as a data point, they're not guaranteed to reflect your current customer base. By building marketing personas, you'll gain a better understanding of your segments on a more personal level, including their wants, needs, pain points, and the context they come to your business with. Ultimately, using market segmentation and marketing personas will help you target your marketing messages and spend more intelligently and efficiently.