We have built a new Data Provider for Data Sync that can be used to Synchronise Lists and Document Libraries including Metadata between some source and Office 365 SharePoint Online. For Example Synchronising Documents between an OnPremise SharePoint Server Document Library and SharePoint Online is quite simple.
We can maintain the Created and Modified values and any folders are also created in SharePoint Online.
With this new Data Provider you can either migrate to SharePoint Online from OnPremise or just publish some of your business data to the cloud. As with everything Data Sync you can setup a regular schedule to push content into SharePoint Online very easily.