I’m seeing this all over the place lately, including here on the SDMB and I’m curious about it. Is it because people are posting on their phones or something? I’m also seeing where every sentence is double-spaced. Here is an example of what I’m talking about:
In many but not all cases, it is the equivalent of bullet pointing. The quoted Weisshund post seems to be an example of this as the rest of the post is a proper paragraph.
Possibly phone thing too, yes.
I do it because it’s much easier to read on a wide monitor.
I always wrote it off to being a cheap easy version of bullet-points. Basically the writing-how-I-speak version of PowerPoint. I can’t complain much; I overuse hyphens. 
Yeah, I think it’s bullet points. I’m on a phone and I don’t post that way.
Sometimes it’s parenthetical, but without parentheses
I lean on this, myself
Huh. I never would have thought bullet points - glad I asked the question!
The whole phenomenon is just one more piece of evidence showing that attention spans keep shrinking.
Humanity is doomed.
These are probably just examples of poor composition. Did you check each posters’ history to find out whether this is common posting style for them?
Whew! Glad I wasn’t used as the example.
I do it sometimes, it is kind of the opposite of the wall of text. Maybe I just went a little too far in the opposite direction.
I used to have a boss that would “skim” emails before replying to them, so I used to make my emails very bulleted, very easy to read. If you bury an important point in a paragraph, it would never been seen. I think it kind of developed from there.
Look at that! At least three sentences in that last paragraph!
I use a different writing style on a message board than I do in normal existence. On a message board, I use much more white space because it makes the text easier to read. Sometimes this turns into one sentence per paragraph, which I’m aware of but choose to go with.
Personally, I have trouble reading an online paragraph that is more than three or four lines. I skip walls of text because they are simply to difficult to wade through.
My texting style is pretty much a return at the end of every sentence, with an occasional double return to break things up.
I have a enough confidence in my own writing to trust my instincts above general rules.
There’s no reason why a paragraph can’t be just one sentence, or even two or three short sentences. Like this one.
If you use the quick reply window, as I’m doing now, sometimes the text will wrap, but when the text is posted in the thread itself, turns out the lines don’t wrap.
(In the quick reply window, the first sentence was two lines long. After posting, it’s only one line.)
Also, as mentioned, people won’t read dense text, which might be as few as four lines. They might read something that looks like bullet points (but don’t count on it). Mostly, they will read the first few words, think they know what the rest of the post is going to say, and quickly respond.
ETA:
True, but that doesn’t answer the question.
Are there any real style rules for a post? We can find well established guidelines for all sorts of forms for the written word, articles, letters, academic papers, etc. On what basis could we pedantically criticize the forms of posts on an online message board?
I’ve noticed that I tend to hit enter after each sentence when posting mobile.
Like this.
It is easier for me to review and proofread.
Since I might be at work or otherwise out & about, there are often interruptions and distractions the keep me from writing an entire post at once.
Paragraphs are indicated as shown.
I’ve also become a bit self consious of my double spaces after sentences.
I know it’s incorrect but it’s how I was taught and the habit is really lodged in there.
One
line
per
paragraph?
Those
guys
aren’t
trying
hard
e
n
o
u
g
h
.
This, too. I’ll read a long post if it’s broken up into readable chunks. Whether it’s actual paragraphs or a few sentences at a time with breaks between them. Post a wall-o- text and you can fuhgeddabouddit.
Sometimes there are different fonts and different screen sizes to contend with.
There are the hazards of composing in one program before cutting and pasting into another (spellcheck, etc.)
Sometimes I’m in a hurry or using a phone with wonky controls, so I might not hit “preview post” to see what it looks like before submitting.
It’s a conscious reaction to the wall of text. Here have one:
Yes, there are occasional carriage returns in there, but great balls of fire that’s painful to wade through on a message board. Make your point, use some white space, and keep things brief and to the point, if possible.
I figured people only read the beginnings of lines, and if I have a point to make or something important to say…
…it goes on a new line.