The purpose of personas is to create reliable and realistic representations of your key audience segments for reference. These representations should be based on qualitative and some quantitative user research and web analytics. Remember, your personas are only as good as the research behind them. Effective personas:

+ Represent a major user group for your website
+ Express and focus on the major needs and expectations of the most important user groups
+ Give a clear picture of the user’s expectations and how they’re likely to use the site
+ Aid in uncovering universal features and functionality
+ Describe real people with backgrounds, goals, and values