PUMS (Public-Use Microdata Samples)
"Microdata files from the American Community Survey show the full range of responses made on individual questionnaires. For example, how one household or one household member answered questions on occupation, place of work, and so forth. The files contain records for a sample of all housing units, with information on the characteristics of each unit and the people in it."
"All identifying information is removed to ensure confidentiality. The records selected are a sample of those households that received the questionnaire. The questionnaire included questions on age, sex, tenure, income, education, language spoken at home, journey to work, occupation, condominium status, shelter costs, vehicles available, and other subjects. For more information click on the following link: Subjects in the American Community Survey PUMS datasets"
"Summary data are predefined cross tabulations of characteristics. The basic unit of analysis is a specific geographic entity -- state, county, etc. -- for which estimates of persons, families, households, or housing units in particular categories are provided."
"In microdata, the basic unit is an individual housing unit and the people who live in it. The record shows all the information associated with a specific housing unit except for names, addresses, or other identifying information."