I frankly have no idea who uses the social media aspects of the site. Some of the “career coaching” groups suggest posting constantly because it ups your visibility to recruiters, but thats only the content generation part. I’d guess some recruiters follow it?
But even with careful curation of my feed, I have no idea who’s spending more than 30 seconds seeing “oh, John/Jane got a new job, cool” and then logging off.
Maybe it’s people stuck trying to find work who think there might, somewhere in the noise, be some useful, additive signal?