I've read so many times on HN that no-one uses FB. Meanwhile, I have friends in many countries around the world I chat with on FB. In India, Russia, SE Asia, Australia, west & east Europe, Africa, latin america etc. The majority of their siblings, parents, children if they have them, are on FB too. So are all their friends. Just about everyone in a lot of countries, seemingly almost all of them, is on there.
I haven't posted anything much in years, maybe once a year. I very rarely look at the news feed. Mostly I'm on FB to chat with friends, and look at their pics if we didn't chat in a while. We exchange pictures, audio, video, PDFs, links etc in the chat. One of these "No-one uses FB" people might look at my wall and think I'm never on FB any more, too, I guess.
I'm not sure if the HN meme of "No-one uses FB" means just "in my circle" and/or "in the USA".. but in the wider world, it does seem like everyone, from 8 to 80, uses it. Everyone with a phone/internet, anyway.
Also, not sure why some people seem to have the idea that FB is just about the news feed and nothing else. As if one is forced to spend all time on FB scrolling the news feed, and if that's bad then FB is useless.