The question <a href="https://mathoverflow.net/q/460824">Most important results in 2023</a> has been posted to MO, and as in previous years, has had a mixed reception. (<b>EDIT:</b> As of this writing, the post has been deleted by the author, presumably because of some negative reactions. It has since been <a href="https://mathoverflow.net/q/461083">reposted by someone else</a>.) Whether such a question is appropriate for MO or not looks to be a recurring issue, and I don't think it has been discussed here on meta before. So, is it appropriate?

The main argument in favor, I think, is that despite some opposition, the analogous question in previous years has overall been received positively, and has received interesting and useful answers. (<b>EDIT:</b> See https://mathoverflow.net/q/83290 and https://mathoverflow.net/q/412437 and https://mathoverflow.net/q/435699 )

An argument against is that it is opinion-based in a bad way, deeming some results "important" and (implicitly, by omission) other results as "unimportant," not only in a narrow subfield, but across all areas of mathematics.

<b>EDIT:</b> Another view may be that the question is okay, but only if rephrased in a way that is less contentious; e.g., "Notable results of 2023."

I don't know if any kind of consensus can be reached here on meta, but it seems worth having a discussion about it that we can point to when the subject comes up again.

<b>EDIT:</b> Quanta Magazine has just published an <a href="https://www.quantamagazine.org/the-biggest-discoveries-in-math-in-2023-20231222/">article</a> ("the biggest discoveries") and a <a href="https://www.youtube.com/watch?v=4HHUGnHcDQw">video</a> (the "biggest breakthroughs") in math of the year. One could argue that Quanta Magazine scratches the itch of those wanting to see such a list, and therefore there is no need for MO to duplicate the list. But another possibility is that the MO question could be changed to, "What results did Quanta miss?"