Online friends were never as important as my RL friends, and I think that's the way it should be.
Then I found an online friend was in trouble with his health, and later read that he had died. I reacted more strongly than I ever thought I would, for someone I had never met and only spoken to a handful of times. I never thought I could care so much about someone online.
And then I found out he had faked it all, and had lied for months about a number of things, from the trivial to the deathly serious.
So now, I assume that largely, all these people could be figments of someone's imagination. Mostly, it's to protect myself from caring as much as I used to.