The limit seems to be 5 avatars per thread. The OP is always first (apparently). Then it seems to be the posters with the most posts in the thread, in descending order. But in short threads, where there are several posters with only one post, what factors determine which of those appear among the avatars shown?
This is completely trivial, idle curiosity on my part. Just wondering.
If you click on the thing to the left of the 5 avatars that says [## users], that’ll pop up the list of the top 24 participants in the thread. Which is OP first, then the most prolific posters in decreasing order, then finally the one-post posters.
Among the one-post posters they seem to be arranged in chrono order of when they posted.
The row of 5 avatars is simply the first 5 of the longer list of 24 inside the pop-up.
Also notice that this feature doesn’t appear at all until the thread grows to a certain number of posts / posters. Right now with 2 posts and two posters it isn’t visible in this thread. Also note that if it appears at all, this same UI element appears just below the OP and also at the end of the thread.
I got the impression it’s actually the four (not five) most prolific participants in the thread, and then the 5th is the last poster. If the last poster is among the most prolific, instead they are highlighted with a blue frame. IIRC.
Unfortunately I am on my phone right now and can’t verify this feature.
That may be a matter of theme. Right now I’m on my Win11 PC w MS Edge running the “Discourse-classic” theme.
Picking a long-running thread at random with 173 users, I see the 5 most prolific are the icons displayed, in descending order of post count. It happens on this thread just now that the last poster is the 6th most prolific overall. But does not appear as the last icon.
I tried a second thread with 64 posters and had the same result. Top 5 are displayed and neither OP nor last poster get special billing.
I don’t recall ever seeing the blue frame you mention. Which may be a failure of my attention, not that the frame doesn’t appear under some circumstances. But which does suggests there may be (are?) some theme-based differences in how the roster is displayed. As you noted, that display is also different on a phone vs a big screen.
The blue frame appears in the category level which also shows 5 avatars for
each thread therein. The first of those is the OP, and if they are also the most
recent poster, then their avatar has a blue frame round it. If they’re not, then
the last avatar is the most recent poster.
A ha! Lightbulb moment.
The OP’s title, but not post body, make it clear they’re talking about the list of avatars that appear on the thread page itself, not on a category page or the new / unread / latest pages.
Thank you @pjd for pointing out there’s a different avatar list with a different rule on those category, etc., pages. I may or may not have understood that before, but I sure wasn’t thinking about it in this thread.
If you hover over the row of avatars on a category etc. page the popup tool tip says the leftmost is the OP & the rightmost is the latest poster. But … The three in the middle are not necessarily the three most prolific other posters in the thread.
Color me baffled about how those three are chosen.
I suspect a lot of it is browser / theme / mobile vs desktop. I will say for my system (Windows 11), Chrome, Dark (not Straightdope Dark) theme, that when I’m at the bottom of an active thread, I see the same as @LSLGuy - the five most active posters without a distinct place for the OP.
But, if I’m looking at a list like Latest, New, or Unread in fullscreen, the 5 posters listed there show the format @ASL_v2.0 mentions: First, 3 top posters, and last, with a light blue circle around the OP if the OP is the lastest poster.