Over 59 distinct cloud services are available to Power BI, such as Google Analytics and Dynamics 365. Most importantly for this project, the Power BI online service is a fully supported data source enabling report development in Power BI Desktop against published datasets. As shown in the following screenshot, the datasets contained in Power BI App Workspaces in which the user is a member are exposed as data sources: 

Leveraging published datasets as the sources for reports provides a natural isolation between the dataset design and report development processes. For example, a dataset designer can implement changes to a local Power BI Desktop file (PBIX), such as the creation of new DAX measures, and re-publish the dataset to make these measures available to report authors. Additionally, these connections provide report authors with visibility to the latest successful refresh of the dataset if the dataset is configured in import mode.