Not to grump, but I assume twitter and facebook all look pretty similar to discourse on a 4k monitor, maximized. But the amount of dollars they sink into UX/UI design is huge, they go for a more column format for a reason, but I think the crux of it is below:
With a standard wide forum design, if people don’t manage their own line brakes, you get run on posts that are super hard to scan and read. The reason newspapers run in columns is you scan articles without having to run your eyes back and forwards. Books do not print their text from the left page to the right page and back again. Again to make it easy to read and scan. All of User ability design for reading in the last 200 years or more, has been about having text in a portrait/column format.
For some reason, classic forums decided to force all posts into being written into letter boxes. This is probably when a lot of forums where first created, everyone had 4:3 aspect ratio monitors. So with the profile picture on the left, and a bit of stuff on the right, made each post into a column format. Once we moved over to 16:10 ratio wide monitors this design has fallen apart.
Now looking at that 4k monitor screenshot does look a bit stupid, and after looking at that screenshot, I wish I had 2 or 3 4k’s instead of 3x1080’s. Because I would be using them as 6 portrait monitors like this:
Windows key+Left Arrow/Right Arrow for the win. Surely you should be on IRC/Livestream and the forums at the same time!
Sorry for being a grump, and I’m not trying to tell you how to use your displays. Just the logic behind the narrower Stream. If I hold up an A4 letter at the distance of my monitors, it is actually pretty close in dimensions to the posts in Discourse.
And just to sort of be grumpy a bit more:
Discourse, column format, reads nice and easy:
Old Forums, run on paragraphs, unnatural to read compared to facebook, news sites, most other day to day reading, etc.
(Also to note, I just hit Alt+PrintScreen, Ctrl+V and Discourse works it out.)
For a none forum example, ArsTechnica:
A news post:
Now from a measurement point of view. The News article text area is 650px wide on ArsTechnica. The text area on discourse is 700px.
Edit: Rob just changed the CSS, and made the the text/post area in discourse about 850px.