Following in Imgur's recent footsteps, Google has decided that come December they will be deleting, among others, all YouTube videos of any account that hasn't been active in at least the last 2 years.
The other stuff may also catch your attention, but for KG itself, only YouTube is really relevant right now.
As with Imgur, KG has been around longer than YouTube. But suffice to say that even more than Imgur being the de facto image uploader of the last decade, YouTube has been internet video for almost the entirety of it.
Please consider backing up