Discussions are only 620px wide? Are you kidding me?

Having options is nice. I personally like the size of the posts, ect because it is very easy for me to read, but I know other people prefer larger text and things more spaced out. In regard to your question, it just depends on how I'm using my computer at the time. If it's the day time and sitting at a desk, I'll usually read in full screen, but if I'm relaxing in my bed like I am now, I prefer a smaller display.

Full screen on 1920? No. But I definitely have my reading area around 1000 pixels wide at all times on sites that use all the space they get (like Reddit). The ~800 pixels the old forums use is workable, but 600 isn't even nearly enough.

I have a 2560x1440 monitor. I have to sit closer to read things. It sucks. :(

I also don't think the space limitations allow for "children" to be properly represented. 600px wide creates an extremely narrow area for you to represent replies to a parent. Your only option is color, and light grey on white isn't a huge separator. I actually wouldn't mind seeing the parent post use a very light teal with a 700-750px wide area, with enough space for proper children responses. I think the discussion drivers (parents), should be easily noticeable. Under the current system due to space limitations and color scheme, they aren't. :(

There's a reason newspapers have always put articles in multiple columns rather than spanning the full width of the paper, and I agree that text is easier to read when it is in narrower columns especially in print. However, reading text on a screen is not the same as on paper. I don't find it more troublesome to read relatively wide bodies of text on my computer, and while I don't have my browser maximized to the full 2560px width of my screen, I do keep it fairly wide. (probably around 1800px) Many web sites don't have a layout that fills the entire width, but almost all sites will fill most of it. In the case of this new community site, the size of the content itself is very narrow and causes more wasted screen space than usual. The narrow width also causes more scrolling than necessary, and I would prefer to be forced to scroll as infrequently as possible.

One of the beautiful advantages that the web has over print is that you don't have to decide on just one format to fit everyone! If one person prefers reading narrow text, then they probably don't keep their browser window as wide as I do. Likewise, if someone has trouble reading small text due to any number of conditions, they can change a setting in their browser to make the text larger. (BTW, another problem with this site: the text size for composing a new comment has a hard-coded font size and doesn't respect user font size settings. The edit box seems to be fine.)