Just because you had a story published in an online publication or uploaded something to a social media site does not mean that your hard work will be forever preserved in digital format for the world to see indefinitely. Backup your writing and keep it safe. For what you post today may be lost tomorrow.
Even if you’re an active member of a social media group, backup your posts if you want to be able to refer to them later in the future. Of course, if what you write and post is of minor significance, then there is no great need to save what you say.
A few years ago, I was actively participating in an online community of writers of microfiction. I posted stories, read the contributions of other members, and exchanged comments and critiques. It was an active community; then one day it ceased to exist. Everything I had written was gone.
The same thing happened to another writer’s community I was a part of. Fortunately, I had just become a member and had not had time to begin contributing so I didn’t lose anything.
The lesson here: the Internet is ephemeral. Publications come and go, social communities come and go. And if you don’t save the work you submit, it will be lost to time and space.