The comment section in a place like HN is convenient for thoughts produced by articles linked here. Moderation takes care of the rest.
I also have a blog despite its slow posting schedule for unrelated thoughts where I want to bring up my own topic, and also have some files lying around on hard drives just for my own notes of no conceivable interest to anyone else. So it's not just "HN" thoughts, it's all kinds of things, technical, philosophical, personal, many different things. In many cases, honestly, these thoughts aren't even that good. I have sometimes read my stuff from 5 years ago sitting on my hard drive and it's all but useless. But it was going to stick around for a long time if I didn't get it out, and then there would be no room for the next thoughts, some of which were useful.
Your mileage may vary, but I know I'm not unique, either. I've seen this attested by many other people as well. We may be the minority case, or we may just be the ones who have learned this lesson, I dunno. I completely lack the data to know how widespread this effect is.
(Some similar concepts may also undergird the effectiveness of talking therapy; if you've got personal issues that you just keep hammering away on in your head, try just writing them down privately. I absolutely, positively can not promise anything, but you may find that simple act gets them out of your headspace. You may then find the next thing, but hey, it can be the beginning of a journey of progress. In the case of talking therapy, it would be getting them out to the therapist in the open, but I think there's a certain amount of evidence, both scientific and anecdotal, that the therapist is not always necessary; simply getting it out in any manner may be the majority of the helpfulness for many people. "It's complicated", of course; there are times and situations where another person being there may be very important.)