Someone did something nice, posted it, others either appreciated it or thought it was interesting and upvoted it. After three years here you should know the answer to this because that question comes up almost every day and it always gets answered in the same way.

With zero submissions to your name there is something you could do if you wanted to change what gets posted to HN.

Well, it's better than "X had died" which pops up about once a day and usually contains someone unrelated to hacker news... While this one is inspiring and good to have on HN