See also public groups/comments on Facebook itself: the realname convention makes most reasonable people self-censor to silence, leaving only the wildest nutcases posting (with rare exceptions in between). Even if you don't use your real name there, as long as you aren't on a dedicated spam account you'll still be connected to your real life network and that is enough for massive self-censoring to happen. Would your hn posts happen if they'd show up in the feeds of distant family? Mine surely would not, and that's while I try keeping hn posts to the highest quality tier of all my online interactions.