Have you found it a bit challenging to get your head around the length, breadth and depth of Office 365. Here is tool that you can use as an anchor to navigate around various options, services, plans and features
Office 365 Service Comparison to filter and compare the features of Office 365 plans, Office 365 services, and on-premises products. As a side note, you get to see the power of Excel Online as well where you get to work with the full size workbook from within the browser to filter and check out features available.
Office 365 Services Descriptors The topics in this library provide detailed descriptions of the services and features that are available with Office 365.