Long ago we had MOOs, MUDs, etc, and they were text based. Just words, you know.
As far as I can tell, there are still quite a few that thrive today. 8) I feel less crazy about my other major hobby now. I've found that there's a lot more flexibility in text-based virtual worlds.
(Disclaimer: I run (and play) text-based MUDs and have not even read the article in question as I don't subscribe to LWN.)