Since June 2011, Office 365 has been the destination for many Exchange, Skype for Business and SharePoint migration projects. Depending on the range of estimates, somewhere between 20-50% of all Exchange mailboxes are currently run from Exchange Online in Office 365.
M365 - Exchange Online Center
ENow Software's Microsoft Exchange Online blog built by Microsoft MVPs for IT/Sys Admins.
Nathan O'Bryan MCSM
Nathan is a five time former Microsoft MVP and he specializes in Exchange, Microsoft 365, Active Directory, and cloud identity and security.
There are a few compelling reasons to move to Office 365, and in my opinion, Office 365 Groups are at or near the top of that list. Office 365 Groups combine resources from across Office 365 in ways that are not possible on-premises to give end users interesting new functionality.
Office 365 Groups (that’s Groups with a capital “G”) are a newish feature of Office 365 that allow for collaboration across several different cloud applications. Office 365 Groups are the cloud only evolution of Site mailboxes, a technology introduced with Exchange and SharePoint 2013 that gave users a single place to access data stored on both Exchange and SharePoint.