I can believe you not hearing about Sharepoint. But not hearing about Onedrive is basically impossible if you have used a Windows machine in the last decade.
Yeah, one may not use it but it's hard to ignore when Office apps suggest you save the document to the cloud as a default. I do avoid it and don't really need any collaboration but I understand that I'm minority. On my home workstation (which is mainly used for video editing) I have only local account so I don't get sucked into more MS services. But at this point you have to actively try to get around the default setup with online account and cloud apps, so it's indeed hard to ignore.
I have never used windows machines for anything but gaming, but I get your point readily. If I had used the windows finder I would have encountered onedrive.
