With the Data Source Library task pane, you can create and manage data connections to a variety of data sources, including lists, libraries, XML files, server-side scripts, XML Web services, Business Data Catalog, linked sources, and Data Sources Libraries on other sites.

Data connections describe a location and query that the Windows SharePoint Services data retrieval service uses to obtain the data from the data sources.

The data retrieval services on the Web server returns data in an XML format that SharePoint Designer and Data Views understand.

SharePoint Designer dynamically creates a data connection for each list, library, and XML file for the current site.

You can copy and modify the data connection, specifying a different set of fields, filters, or sort order for a specific data source.

The fields and filters defined in the data connections control the amount of data that is retrieved from the data sources. Consider carefully your data connection configuration to minimize the load on the Web servers, the amount of data transmitted over the network, and the time to render a page.

Web Parts, including Data Views, can exchange data by using Web Part connections.