Likely it wasn't in the title when this poster posted it, 2 hours before you replied. It's common on HN for older stories to get posted and get upvoted to the

Likely it wasn't in the title when this poster posted it, 2 hours before you replied. It's common on HN for older stories to get posted and get upvoted to the front page, and commenters will make a note in the comments that it is an older story and should be marked as such in the hopes that the mods will notice and add e.g. (2015) to the title. The tersest way to do this is to simply post a top level comment with the year the article was written, surrounded by parentheses.