API and Apps: An example fom official statistics

An example of an API access to statistical data

The U.S. Census Bureau  now offers some of its public data in machine-readable format. This is done via an Application Programming Interface (“API”).
Based on this API an App has been developed helping to query data from the Cenus 2010:

No data without legal clarification. The Census Bureau does it like follows:

‘Use
You may use the Census Bureau API to develop a service or service to search, display, analyze, retrieve, view and otherwise “get” information from Census Bureau data.
Attribution
All services, which utilize or access the API, should display the following notice prominently within the application: “This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.” You may use the Census Bureau name in order to identify the source of API content subject to these rules. You may not use the Census Bureau name, or the like to imply endorsement of any product, service, or entity, not-for-profit, commercial or otherwise.’