NOW RELEASED and To sum it up in one little sentence
"Relationship Insights leverages the data-integration and artificial-intelligence capabilities built into Azure to combine and analyze your Dynamics 365 and Microsoft Outlook data" -365Blog
And just think this is part of Microsoft Dynamics 365 Online - OH The potential, the power, the depth of new insights
If you want to read more about Microsoft Dynamics 365 Online Relationship Insights then check out this blog post that the team wrote up when the feature was in preview.