A person account is an individual consumer with whom you do business. Person accounts are applicable to organizations that operate on a business-to-consumer model as opposed to a business-to-business model. They must be enabled by support, and once enabled can never be disabled.
n a business-to-business model, there is a natural differentiation between the other businesses with whom you work and the people associated with those businesses. In Salesforce, that translates to accounts and contacts having different fields, features, and tabs. In a business-to-consumer model, because you are providing products or services to people rather than companies or organizations, the distinction between accounts and contacts does not exist. Consequently, person accounts in Salesforce have a combination of fields from both accounts and contacts, and can be used as contacts in most situations that involve contacts. For example, business accounts do not have standard fields for email address and job title, but person accounts do. Also, person accounts can be associated with campaigns just like contacts, but business accounts cannot.