A Microsoft file hosting and synchronization service.
While I agree that this info is good to know, the basic premise is that this improves the files-on-demand feature. I don't use that feature, so they really messed up the Onedrive experience for those of us not using files-on-demand. MS really needs to understand their user-base before making such drastic changes, and deleting all my files :( (Fyi, I found your post very helpful; thanks for including it here)