Introducing Microsoft Stream!

Yeah lots of forums to read/follow.

In short O365 Video vs Stream...

We started Stream to be able to have an enterprise video offering from Microsoft for those customers who aren't ready to purchase enterprise suite licenses for O365.

Longer...

Stream is in preview only but has a few cool features not yet in O365 Video: Watch list, like, #hash tags, videos can be in multiple channels, permissions at the video level (not at channel level)

O365 Video is generally available and has other features not yet in Stream: Portal/channel curation, video statistics (view/visitor trend and which part of video viewed), IT Admin controls, O365 Tier C compliance, videos show up in enterprise search, videos show up in Delve, videos/channels on SharePoint Home and SP Mobile App, public REST API.

Over the course of time we'll converge O365 Video and Stream to have one solution. Right now they are both built on top of Azure Media Services but their mid-tiers are different technologies. We need to build feature, admin, compliance, and O365 integration parity into our converged solution first. 

For now we still want all our current and future customers who have E/A/G licenses to continue (and start) using O365 Video. If/when we need to do some sort of migration we'll take care of everything for you as painlessly and seamlessly as possible. It should feel more like O365 Vidoe just got renamed to Stream and got new UI/features and iterated than anything else. Videos, metadata, stats, links, embed codes will continue to keep working in our converged solution.