In my work with personas, there's one question that comes up the most often: "Aren't personas the same as market segments?"
Actually, the question is most often phrased as a statement: "Oh, we already have personas, because we have market segmentation."
I often respond by asking another question: "If you owned a playhouse, which is more important, hiring people to sell tickets or hiring an acting troupe to put on a play? It's a ridiculous question, because both activities are essential. Different types of people fulfill different needs, all of which must work for the business to function.
Market segments and personas are different tools for different purposes. Where market segments help you target qualified potential customers, personas help you satisfy these people. Working together, they complete the loop by helping you generate demand and then satisfy that demand.
First and foremost, market segments are about finding the best ways to target and deliver marketing messages that create demand. The entire population of potential customers is segmented into groupings that, because of core differences between them, are likely to respond to a variety of marketing channels and messages. This segmentation helps forecast market acceptance and predict purchasing behavior.
Because the goal is to get customers' attention, persuade and create demand, market segmentation has historically been based on variables that correlate to creating demand: geography, age, gender, income, education, occupation and other traditional demographics, as well as psychographics around personality, lifestyle, values and attitudes. It works because these attributes are helpful for defining how to effectively speak to different groups of people.
Personas, on the other hand, are for understanding how people will actually engage with you. Let's say you're running a real estate website and have already established market segments for creating demand. Those segments define what marketing programs are going to be most successful, but they don't help for making decisions about how the site should actually work or how it should be designed. Knowing that a particular segment has an average age of 41 doesn't help you define which website features you should build next. Knowing where your segments live doesn't help you decide what the site navigation should be or what imagery to use. For making decisions about site features, content, structure and design, you need a different kind of segmentation driven by different characteristics.
Personas are segments defined primarily by goals and behaviors, because these attributes are most important for making the decisions listed above. Goals reveal why people come to the site and what they're trying to do, and behaviors show how they expect to accomplish their goals. For a real estate site, if you have a segment whose goal is to find an apartment, you have the foundation for determining which content and features are going to be needed to help that segment. If you know a segment's behaviors and attitudes (for example, if people in this segment typically prefer personal contact and are intimidated by the process of finding the right apartment), you can make effective decisions about exactly how to create, structure and design those features and content.
By the way, personas are not the same as roles or job titles. Creating an Executive persona and an Administrative Assistant persona usually isn't the way to go, because not all executives have the same goals or act the same way. Segmenting by goals and behaviors is more successful, because what people are trying to do and how they want to do it often don't correlate to their job titles. In the end, you might discover three different executive-type personas and no admin persona, because the latter's goals and behaviors are already represented in one of the executive personas.
In essence, market segments answer the "Who" and "What" questions: Who do you target, what products or services do they need, what are they likely to purchase and at what price point, what marketing programs can successfully reach them, and so on.
Once you know what your product is, personas help you answer the questions of "Why" and "How." Why does this product or service make sense to your target audience? Why do the people represented in this audience need it, and why will they use it? How should we structure and design it to satisfy how people will be using it? How do we make sure the site gives people the experience they need and the business results we need?
Both methods are essential for creating and implementing a successful web strategy, and both tools are evolving based on this symbiosis. Market segments are increasingly incorporating goals and behaviors to provide a more complete portrait of potential customers earlier in the process. Personas, once a touchy-feely qualitative design tool, are benefiting from the rigor of market segmentation by incorporating quantitative techniques such as statistical analysis of survey data.
Market segments and personas collectively provide a holistic understanding of our customers, including how to get them to our door, how to invite them inside, and how to satisfy them so that they'll return. These techniques, when combined, close the marketing and delivery loop, which is why they are both needed for making websites successful.