A Microsoft file hosting and synchronization service.
Exactly my question since I've made the huge mistake of trying to use it for the first time yesterday. Incredibly confusing, ultimately awful.
I recently upgraded my laptop and switched to MS 365 and it kept pushing OneDrive on me. As I'm working on a document that I'd like to be "backed-up" frequently, I thought "nice, I'll give this a go".
What a nightmare. I spent an entire day trying to understand what on earth was happening, why my files were disappearing from my PC, trying to figure out where the auto-save function on Word was actually saving the file (freaked out a bit when I noticed it wasn't saving changes on the SAME document I was making them on, but created a NEW file EVERY TIME I closed and opened the document, which I couldn't immediately locate). I've finally figured out I could at least select what to sync (!), thought "ok, this should work..."
Except, today I created a test file to see if the sync works... OneDrive claims that it is synced... I click directly on the file and it opens on onedrive.live... but is nowhere to be found when I go to my cloud account.
Granted, it can just be claimed all of this is "normal" and that *I* just couldn't figure it out...
...which is exactly the problem.
I'm done.
What a nightmare.