Why not also have author names at the bottom, while you're at it.

I second the request. I already shared this idea with Ruby and he said he liked it (he might have also thought about it himself before, I don't remember). Probably just didn't get around to it yet.

This seems a lot easier to backfire, because often we filter what to even start reading based on more quickly-digested summaries (probably quite rightly), which include karma and the like, as well as recommendations. It might work better, for that reason, if at all, on comments than on top-level posts.

Without (yet) commenting on the mechanism itself, I'll provide my self-observation that I almost never use top-level post karma for explicit prefiltering, whereas I use comment karma for prefiltering primarily on the implicit level provided by the way they are sorted in the interface but also to a lesser degree on an explicit level. I attribute this retrospectively to:

1. Top-level posts being fewer and of less variable quality to begin with.
2. More of the variance in which top-level posts I want to read being based on topic. By comparison, more of the variance in which comments I want to read conditioned on them being on a specific top-level post that I'm already interested in is based on quality. (Quality implicitly includes “on-topic” in that context anyway.)
3. The positioning of the UI elements in posts versus topics.

(3) is something that I notice is surprising to me now that I think about it. I barely notice the voting elements for posts—why is that? They're not particularly small in size, and while they're lower-contrast than the main text, this is also true for comments. I would guess it's mainly geometry and flow. When I start reading a comment, the eye-catching header in bold leads straight into the time-since and karma display on the same line. But when I'm reading a post from the front page, the karma is part of the second, longer “metadata” line that I skip over as an entirely different group. When I'm reading a post by itself, the voting gadget is off to the side of the title and uses vertical arrows, again an entirely different group that I skip over visually. The second voting gadget between the main article and the comment section, I think, gets subsumed—the gap is what I'm scanning for when I'm trying to scroll to the comments, and then it reads as “a bunch of whitespace (that's the important part) that happens to have a voting gadget in it for ornamentation”. The latter may as well be one of those fancy curly figures that get used as separators in books sometimes.

To be clear, my more controversial speculation does not go up to scanning the user's brain to confirm their ingestion, digestion, and careful consideration of the post's content^[1] before allowing them to cast votes.

It does seem important that people be able to sometimes express 'I would like more people to see this (kind of thing) after my superficial read but I don't have time to digest in detail now', but it might be a good thing if this were necessarily at least a tiny bit deliberate.