The most memorable one for me was I had decided to invest $100 into bitcoin when it was under $1. I went to an exchange, created an account, and then chickened out when they asked for my bank info. I just didn't trust the exchange yet since it was so new. Could've been retired by now :)
The rise of data-science and the global impact of COVID were two other trends that I was aware of "ahead of time" due to regular reading of HN.
What trends have you seen coming that (with the benefit of hindsight) you had a pretty good feeling would be big because of the coverage here? Any trend predictions that were way off?
I don't dare try to list any beyond that. The fact of the matter is, I'm gullible when it comes to reading most HN comments, so I don't tend to recognize HN group-think until some other poster points it out.
I don't know if it is because of the lack of text formatting, my lack of knowing that there are people behind the usernames, but as long as someone doesn't type something that trips the off-topic/downvote-o-meter, the various voices all blend together into one large somewhat reasonable sounding blob...at least until someone says something that I have a strong knowledge (or belief of strong knowledge) of, then I have an opinion.