Data sources can be either embedded or reusable. Reports can include both embedded and reusable data sources.
Data sources that you create while editing a report are embedded in the report. To edit an embedded data source, you do so within that report. Embedded data sources make collaborating on reports and data sources easier. Anyone who can edit the report can also edit the data source, as well as modify its connection. When you share or copy the report, any embedded data sources are shared or copied as well.
Data sources that you create from the home page are reusable. You can reuse these data sources in different reports. Reusable data sources let you create and share a consistent data model across your organization. Only people with whom you share the reusable data source can edit it. Only the owner of the data source's credentials can modify the connection.