It's a bare-bones Twitter clone made by Meta. There's no interesting new technology to discuss, no open source angle, no discussion on the company founder that hasn't been done 100 times.
HN has plenty of discussions about interesting Meta projects - Quest, React, the metaverse, financial discussions, etc. I just don't think there's much to grip people on this topic.
At least, the first time in a while
YouTube Shorts also exists to compete with TikTok.
I can't actually think of the last time one of the existing networks launched a new app to compete rather than just stealing UX features, that is a new one to me for sure!
Regardless I do think its funny that Facebook had photos but Instagram is still a product and now Facebook has always had status updates and now Threads is a product. Facebook is almost just a mashup of Instagram + Threads. Or in a way some demographic of users liked a Facebook experience but for photos only (Instagram) and another set of users liked a Facebook experience but for status updates only (Threads).