Actually, I would say 40 characters per line is way too little for my own comfort unless I'm reading brief summaries that lead to full articles elsewhere. Otherwise, I prefer 80 to 110, I think. I don't feel comfortable going beyond that, though.
Okay, but it is generally accepted (as best I can remember from doing my BA, in English and the Humanities) that a average (English) word is five characters. So before the days of word processors which do word counts, you could just count the pages if you had to write 2000 words. That means 80-110 should be 15-20 words per line, including a space between words. That I have no problem with, altho I do really, for myself, find that minimal -- I'd rather read a file with 140 char lines than one with 65, by a long shot. But, as I will shortly demonstrate, most fixed width pages actually have 50 characters per line or less (and you can go check that yourself).
I would argue, also, that most periodic literature does use multi-column layout. Looking at several magazines I have here, I can't find one that uses single columns.
I agree. I actually don't like magazines much -- nothing in particular about them, I just almost never come across one that I find interesting enough to read for more than 5 minutes. I rarely even finish an article (and I rarely start one, either). But I totally enjoy books and always have. I think most of that 500 year history is about books. The "developments" that occurred with printing in the 20th century I am sure have to do with making room for ADVERTISING. I'm pretty neutral about advertisizing, I don't quite consider it the work of the devil or anything, but I think most people,
given a choice, would prefer to avoid it. You tolerate it in magazines and web sites because you know that it helps to pay for it, and maybe that is even a good thing.
But designers who have been immersed in this superficial and semi-literate world for long enough I think seem occasionally to have this "zombie" response where they just automatically must include columns of clutter
even if it is not paid ads. Now, I have ADHD, but even I find this silly and condescending. Or maybe because I have ADHD??
I also have an O'Reilly book on ActionScript 3 here which uses two columns (1 for the primary content and 1 for asides). The primary content column, where there are no asides, is about 3/5ths of the page width - about 80 characters per line in a 10pt Times.
I actually have Actionscript Cookbook and Essential Actionscript 2.0 here by O'Reilly (both from the library; I haven't really read them much yet since I don't have as much time as I was hoping for flash). A normal O'Reilly page is 80 characters right across.
Now, I know part of my personal pet peeve here is because of the 22px font. I know I said 22pt before, but I make it a habit to not set font sizes (beyond <h>) so I don't pay attention to them and after doing a little digging realized "22" in FF refers to pixels. Which is quite a bit smaller than 22pts.

So going with a 1000px width, we should get 50 characters per line. That's without sidebars that are 250 px wide each. Even with a 10px font (which is going to be smaller than average) a 500-600px column is still only 50-60 characters. That is 25-30% less than 80. At 22px, it is just stupid.
So this is my point: LEAVE THE USER THE FREEDOM TO CHOOSE. I know everybody is enamoured with their own creativity, but I really think an obsession with
font sizes and
page width -- whereby you must set these exactly in order to get your page "just right" -- is a sure sign this creativity has been coerced in the wrong direction.
I do not do much professional web work, but I know that clients are an issue here. I have had someone I was doing work for point me to sites he liked and they were all fixed width, and when I showed him my idea he said, literally, "Well, it does not look like a magazine like these other sites; there should be space down the sides". Pushing my point a bit, I wrote him an explanation about not constraining the
user interface (which is not a magazine) and about distributing whitespace evenly, rather than putting it down the side and squishing all the content into the middle, and (personal opinion) that the reason fixed width sites exist is because they are easier to code. Then I said if he really insisted, I would do that, but I thought it was a bad idea. The next day he agreed. Of course, not everyone is like that and I am sure clients are a sad factor here.
Let's design our own study!!!

It probably would be a good poll. However, it's not my intent to win a popularity contest vis. how many words you like in your line, because that implies that this is an issue which everyone should vote on and let the majority decide for everyone else. Even if I were (maybe I am!) in the majority on this, I would not want to make it a rule for everyone else. Which, like I've been trying to emphasize, the user (often can) make a choice buying a monitor, and certainly they have a choice manipulating the browser window and setting the preferences. That is the nature of the beast. It just seems backward and ignorant to me to decide to pretend these things are not real and that you must present an 8 1/2" x 11" flyer, because of this dufus at the London Times or where-ever.
Oh, on the perldoc thing, I find the color scheme more offensive than anything.

Yeah, there were some things said about that at perlmonks too

I almost felt sorry for the guy until I exchanged a series of emails with him (kudos, at least he was interested in my criticism) and it became clear he was sticking to his guns, etc, in which case you get what you deserve if people
repeatedly say look, honestly you have made a mistake and screwed up here. Get over it.
This is the old perldoc; FF is 1680px wide with a minimum 22px font. Works great! Looks great! Now browsing over to the new one, the word
devolution springs to mind. I understand if the guy wants to do comic books instead -- nothing wrong with that -- but really (as much as I might sometimes like it if it were) perl documentation is not a comic book, or
Newsweek. It is technical documentation...